ast@cs.vu.nl (Andy Tanenbaum) (12/18/89)
It has been pointed out to me that I nroffed the /usr/man/man1 file 80
columns wide, which is a disaster if you have LINEWRAP on. I have it off,
so I didn't notice. Here is a revised version, 79 columns wide. Cat this
and the next file together and install in /usr/man/man1.
Andy Tanenbaum (ast@cs.vu.nl)
----------------- cut here for first part of /usr/man/man1 --------------
#animals
Command: animals - twenty questions type guessing game about animals
Syntax: animals [database]
Flags: (none)
Example: animals # Start the game
Animals is a guessing game. The user picks an animal and the computer tries
to guess it by posing questions that should be answered by typing ``y'' for yes
and ``n'' for no. Whenever the computer loses, it asks some questions that
allow it to improve its data base, so as time goes on, it learns. The default
data base should be in /usr/lib/animals.
#ar
Command: ar - archiver
Syntax: ar [qrxdpmt][abivulc] [posname] archive file ...
Flags: (none)
Examples: ar r libc.a sort.s # Replace sort.s in libc.a
ar rb a.s libc.a b.s # Insert b.s before a.s in libc.a
Ar allows groups of files to be put together into a single archive. It is
normally used for libraries of compiled procedures. The following keys are
allowed:
q: quickly append to the end of the archive file.
m: move named files. Ar expects a, b, or i to be specified.
r: replace (append when not in archive).
d: delete. Ar will delete the named members.
t: print the archive's table of contents.
p: print the named files (list them on stdout)
x: extract
The keys may optionally concatencated with one or more of the following:
l: local temporary file for work instead of /tmp/ar.$$$$$
v: verbose
a: after posname
b: before posname
i: before posname
c: create (suppresses creation message)
u: replace only if dated later than member in archive
#ascii
Command: ascii - strip all the pure ASCII lines from a file
Syntax: ascii [-n] [file]
Flags: -n Extract the lines containing nonASCII characters
Examples: ascii file >outf # Write all the ASCII lines on outf
ascii -n <file >outf # Write all thenonASCII lines on outf
Sometimes a file contains some nonASCII characters that are in the way.
This program allows the lines containing only ASCII characters to be grepped
from the file. With the -n flag, the nonASCII lines are grepped. No matter
whether the flag is used or not, the program returns an exit status of true if
the file is pure ASCII, and false otherwise.
#asld
Command: asld - assembler-loader
Syntax: asld [-d] [-s] [-o name] file...
Flags: -L A listing is produced on stdout
-T Used to specify a directory for the temporary file
-o Output goes to file named by next argument
-i Use separate I & D space (64K + 64K)
-s A symbol table is produced on stdout
Examples: asld -s file.s # Assemble file.s and list symbols
asld -o output file.s # Assemble file.s, put binary on output
asld -T. file1.s file2.s # Use current directory for temporary file
Asld is the MINIX assembler and loader combined. It accepts a language
similar to that accepted by the PC-IX assembler. Symbols are made up of
letters, digits and underscores. The machine instructions and addressing modes
are the same as those used by PC-IX, except that modes using multiple registers
are written like this example: mov ax,(bx_si). Constant operands are denoted
by a number sign. Local labels are permitted in the usual UNIX style: the
instruction jmp 1f jumps forward to the closest label 1:
The pseudoinstructions accepted by the assembler are listed below:
.align n Align to a multiple of n bytes
.ascii strAssemble a string
.asciz strAssemble a zero-terminated string
.bss What follows goes in the bss segment
.byte n Assemble one or more bytes
.data What follows goes in the data segment
.define symExport sym from the file
.errnz n Force error if n is nonzero
.even Align to an even address
.extern symDeclare sym external
.globl symSame as extern
.long n Assemble n as a long
.org adr Set address within current segment
.short n Assemble n as a short
.space n Skip n bytes
.text What follows goes in the text segment
.word n Assemble n as a word
.zerow n Assemble n words of zeros
In the above pseudoinstructions, adr is an expression yielding a machine
address, n is a numeric expression, str is a quoted string, and sym is a sym-
bol. The library /usr/lib/libc.a is a packed archive of assembly code. To see
some examples of it, extract some files from the archive with ar and then use
the filter libupack to convert them to readable ASCII.
MINIX does not use .o files. Compiler output is packed assembly language,
as are the modules in an archive. This scheme requires reassembling archive
modules all the time, but it saves precious diskette space.
#ast
Command: ast - add symbol table to executable file
Syntax: ast [-xX] [file] [symbol_file]
Flags: -x Do not preserve local symbols
-X preserve
Example: ast -X a.out # Add symbols from symbol.out to a.out
Ast adds the symbol table produced by the -s option of asld to the execut-
able file. If no symbol table file is listed, the default name symbol.out is
used. The symbol table can be generated by the command cc -s file.c
>symbol.out.
#at
Command: at - execute commands at a later time
at time [month day] [file]
Flags: (none)
Examples: at 2315 Jan 31 myfile # Myfile executed Jan 31 at 11:15 pm
at 0900 # Job input read from stdin
at 0711 4 29 # Read from stdin, exec on April 29
At prepares a file to be executed later at the specified time by creating a
special entry in /usr/spool/at. The program atrun should be started periodi-
cally, for example, every minute by cron. Atrun checks to see if any files in
/usr/spool/at should now be run, and if so, it runs them and then puts them in
/usr/spool/at/past. The name of the file created in /usr/spool/at by at is
YY.DDD.HHMM.UU (where YY, DDD, HH, and MM give the time to execute and UU is a
unique number). Note that when the command runs, it will not be able to use
stdin or stdout unless specifically redirected. In the first example above, it
might be necessary to put >/dev/tty0 on some lines in the shell script myfile.
The same holds for the commands typed directly to at.
#backup
Command: backup - backup files
Syntax: backup [-dmnvz]
Flags: -d At top level, only directories are backed up
-j Do not copy junk: *.o, *.Z, *.bak, a.out, core, etc
-m If device full, prompt for new diskette
-n Do not backup top-level directories
-s Do not copy *.s files
-t Preserve creation times
-v Verbose; list files being backed up
-z Compress the files on the backup medium
Examples: backup -mz . /f0 # Backup current directory compressed
backup /bin /usr/bin # Backup bin from RAM disk to hard disk
Backup (recursively) backs up the contents of a given directory and its sub-
directories to another part of the file system. It has two typical uses.
First, some portion of the file system can be backed up onto 1 or more
diskettes. When a diskette fills up, the user is prompted for a new one. The
backups are in the form of mountable file systems. Second, a directory on RAM
disk can be backed up onto hard disk. If the target directory is empty, the
entire source directory is copied there, optionally compressed to save space.
If the target directory is an old backup, only those files changed since the
backup was made are copied. Backup uses times for this purpose, like make.
#badblocks
Command: badblocks - put a list of bad blocks in a file
Syntax: badblocks block_special
Flags: (none)
Example: badblocks /dev/fd1 # Handle bad blocks on /dev/fd1
If a device develops bad sectors, it is important to not have them allocated
to important files. This program makes it possible to collect up to 7 bad
blocks into a file, so they will not be allocated for a ``real'' file. When the
program starts up, it asks for a list of bad blocks. Then it creates a file
whose name is of the form .Bad_xxxxx, where xxxxx is a pid.
#banner
Command: banner - print a banner
Syntax: banner arg ...
Flags: (none)
Example: banner happy birthday # Print a banner saying happy birthday
Banner prints its arguments on stdout using a matrix of 6 x 6 pixels per
character. The @ sign is used for the pixels.
#basename
Command: basename - strip off file prefixes and suffixes
Syntax: basename file [suffix]
Flags: (none)
Examples: basename /user/ast/file # Strips path to yield file
basename /user/file.c .c # Strips path and .c to yield file
The initial directory names (if any) are removed yielding the name of the
file itself. If a second argument is present, it is interpreted as a suffix
and is also stripped, if present. This program is primarily used in shell
scripts.
#bawk
Command: bawk - pattern matching language
Syntax: bawk rules [file] ...
Flags: (none)
Examples: bawk rules input # Process input according to rules
bawk rules - >out # Input from terminal, output to out
Awk is a pattern matching language. Bawk is Basic Awk, a subset of the ori-
ginal. The language is described in /usr/doc/bawk.doc. The file name - can be
used to designate stdin.
#btoa
Command: btoa - binary to ascii conversion
Syntax: btoa [-adhor] [infile] [outfile]
Flags: -a Decode, rather than encode, the file
-d Extracts repair file from diagnosis file
-h Help menu is displayed giving the options
-o The obsolete algorithm is used for backward compatibility
-r Repair a damaged file
Examples: btoa <a.out >a.btoa # Convert a.out to ASCII
btoa -a <a.btoa >a.out # Reverse the above
Btoa is a filter that converts a binary file to ascii for transmission over
a telephone line. If two file names are provided, the first in used for input
and the second for output. If only one is provided, it is used as the input
file. The program is a functionally similar alternative to uue/uud, but the
encoding is completely different. Since both of these are widely used, both
have been provided with MINIX. The file is expanded about 25 percent in the
process.
#cal
Command: cal - print a calendar
Syntax: cal [month] year
Flags: (none)
Example: cal 3 1992 # Print March 1992
Cal prints a calendar for a month or year. The year can be between 1 and
9999. Note that the year 91 is not a synonym for 1991, but is itself a valid
year about 19 centuries ago. The calendar produced is the one used by England
and her colonies. Try Sept. 1752, Feb 1900, and Feb 2000. If you don't under-
stand what is going on, look up Calendar, Gregorian in a good encyclopedia.
#cat
Command: cat - concatenate files and write them to stdout
Syntax: cat [-u] file...
Flags: -u Unbuffered output
Examples: cat file # Display file on the terminal
cat file1 file2 | lpr # Concatenate 2 files and print result
Cat concatenates its input files and copies the result to stdout. If no
input file is named, or - is encountered as a file name, standard input is
used. Output is buffered in 512 byte blocks unless the -u flag is given.
#cc
Command: cc - C compiler
Syntax: cc [-FRSTUciosuw] [-Dname]... [-Idir]... [-LIB] file ...
Flags: -D The flag -Dx=y defines a macro x with value y
-F Use a file instead of a pipe for preprocessor output
-I -Idir searches dir for include files
-LIB Produce a library module
-R Complain about all non Kernighan & Ritchie code
-S Produce an assembly code file, then stop
-T The flag -Tdir tells cem to use dir for temporary files
-U Undefine a macro
-c Compile only. Do not link. (Same as -S)
-i Use separate I & D space (64K + 64K)
-o Put output on file named by next arg
-s Include symbol table in executable file
-v Verbose. Print pass names
-w Suppress warning messages
Examples: cc -c file.c # Compile file.c
cc -D_MINIX file.c # Treat the symbol _MINIX as defined
cc -c -LIB file.c # Make a module for the library
cc -R -o out file.c # Check for K & R; output to out
This is the C compiler. It has five passes, as follows:
Program Input Output Operation performed
/lib/cpp prog.c prog.i C preprocessor: #include, #define, #ifdef
/lib/cem prog.i prog.k Parsing and semantic analysis
/usr/lib/opt prog.k prog.mOptimization of the intermediate code
/usr/lib/cg prog.m prog.sCode generation
/usr/lib/asld prog.s a.outAssembly and linking
The main program, cc, forks appropriately to call the passes, transmitting
flags and arguments. The -v flag causes the passes to be listed as they are
called.
The -c or -S flags stop compilation when cg has produced an assembly code
file (in packed format) because the current assembler-loader expects that (see
under File Formats later in this appendix). The libraries are also archives of
packed assembly code files, except that defined symbols must be declared by
.define statements at the beginning. To make modules for inclusion in the
library, use the -c and -LIB options. There is no way to get .o files; the
packed assembly language files are used as a substitute. They can be unpacked
with the filter libupack.
The -R flag gives warnings about all constructions not permitted by official
Kernighan and Ritchie C. The average garden-variety C program that has been
flawlessly acceptedly by most C compilers contains surprisingly many illegal
constructions. Try it.
The compiler normally keeps cpp and cem in memory at the same time,
transferring the output of cpp to cem using a pipe. However, if there is
insufficient memory available to hold both at once, the -F flag can be given to
cause these two passes to be run strictly sequentially, with the preprocessor
output being stored on a file in /tmp (unless -T is used). When available
memory is very limited (e.g., a 512K machine), it may be necessary to run chmem
to reduce the sizes of the compiler passes that do not fit, typically cem.
The other passes, especially asld, can create large temporary files in /tmp.
To compile very large programs, first type
cc -c *.c
to get .s files. Then remove /lib/cpp and /lib/cem and possibly other files
from the RAM disk to make more space for /tmp. Finally, type
cc *.s
which results in
asld /usr/lib/crtso.s *.s /usr/lib/libc.a /usr/lib/end.s
to produce the a.out file. The files removed from the RAM disk can be restored
by mounting the root file system and copying them from there, or the system can
be shut down and rebooted.
If the compiler (or, in fact, almost any program) begins acting strange, it
is almost always due to its running out of space, either stack space or scratch
file space. The relevant pass can be given more stack space using chmem. More
space for scratch files can be obtained by removing other files on the device.
The compiler is derived from the ACK system (Tanenbaum et al., 1983), not
from the AT&T portable C compiler. It has been shoehorned onto the PC with
some loss of performance.
#cdiff
Command: cdiff - context diff
Syntax: cdiff [-c] old new
Flags: -cn How much context to provide
Examples: cdiff old new >f # Write context diff on f
cdiff -c1 old new >f # Use only 1 line of context
Cdiff produces a context diff by first running diff and then adding context.
Some update programs, like patch, can use context diffs to update files, even
in the presence of other, independent changes.
#cgrep
Command: cgrep - grep and display context
Syntax: cgrep [-a n] [-b n] [-l n] [-w n] pattern [file] ...
Flags: -a How many lines to display after the matching line
-b How many lines to display before the matching line
-f Suppress file name in the output
-l Lines are truncated to this length before comparison
-n Suppress line numbers in the output
-w Sets window size (same as -a n -b n)
Example: cgrep -w 3 hello file1 # Print 3 lines of context each way
Cgrep is a program like grep, except that it also can print a few lines
above and/or below the matching lines. It also prints the line numbers of the
output.
#chgrp
Command: chgrp - change group
Syntax: chgrp group file ...
Flags: (none)
Example: chgrp system file1 file2 # Make system the group of the files
The group field of the named files is changed to group. Alternatively, a
decimal gid may be specified instead of a user name. Only the super-user may
execute this command.
#chmem
Command: chmem - change memory allocation
Syntax: chmem [+] [-] [=] amount file
Flags: (none)
Examples: chmem =50000 a.out # Give a.out 50K of stack space
chmem -4000 a.out # Reduce the stack space by 4000 bytes
chmem +1000 file1 # Increase each stack by 1000 bytes
When a program is loaded into memory, it is allocated enough memory for the
text and data+bss segments, plus an area for the stack. Data segment growth
using malloc, brk, or sbrk eats up stack space from the low end. The amount of
stack space to allocate is derived from a field in the executable program's
file header. If the combined stack and data segment growth exceeds the stack
space allocated, the program will be terminated.
It is therefore important to set the amount of stack space carefully. If
too little is provided, the program may crash. If too much is provided, memory
will be wasted, and fewer programs will be able to fit in memory and run simul-
taneously. MINIX does not swap, so that when memory is full, subsequent
attempts to fork will fail. The compiler sets the stack space to the largest
possible value (for the Intel CPUs, 64K - text - data). For many programs,
this value is far too large. Nonrecursive programs that do not call brk, sbrk,
or malloc, and do not have any local arrays usually do not need more than 8K of
stack space.
The chmem command changes the value of the header field that determines the
stack allocation, and thus indirectly the total memory required to run the pro-
gram. The = option sets the stack size to a specific value; the + and -
options increment and decrement the current value by the indicated amount. The
old and new stack sizes are printed.
#chmod
Command: chmod - change access mode for files
Syntax: chmod octal-number file ...
chmod [augo][+-=][rwxst] file ...
Flags: (none)
Examples: chmod 755 file # Owner: rwx Group: r-x Others: r-x
chmod +x file1 file2 # Make file1 and file2 executable
chmod a-w file # Make file read only
chmod u+s file # Turn on SETUID for file
chmod g=u # Group perms set to same as user perms.
The given mode is applied to each file in the file list. The mode can be
either absolute or symbolic. Absolute modes are given as an octal number that
represents the new file mode. The mode bits are defined as follows:
4000 Set effective user id on execution to file's owner id
2000 Set effective group id on execution to file's group id
0400 file is readable by the owner of the file
0200 writeable by owner
0100 executable by owner
0070 same as above, for other users in the same group
0007 same as above, for all other users
Symbolic modes modify the current file mode in a specified way. They take the
form:
[who] op permissions { op permissions }
The possibilities for [who] are u, g, o, and a, standing for user, group, other
and all, respectively. If [who] is omitted, a is assumed, but the current umask
is used. The op can be +, -, or =; + turns on the given permissions, - turns
them off; = sets the permissions exclusively for the given who. For example g=x
sets the group permissions to --x.
The possible permissions are r, w, x; which stand for read, write, and exe-
cute; s turns on the set effective user/group id bits. u, g and o in the per-
missions field stand for the current user, group, or other permission bits,
respectively. Only one of these may be used at a time. s only makes sense with
u and g; o+s is harmless and does nothing. Multiple symbolic modes may be
specified, separated by commas.
#chown
Command: chown - change owner
Syntax: chown user file ...
Flags: (none)
Example: chown ast file1 file2 # Make ast the owner of the files
The owner field of the named files is changed to user (i.e., login name
specified). Alternatively, a decimal uid may be specified instead of a user
name. Only the super-user may execute this command.
#clr
Command: clr - clear the screen
Syntax: clr
Flags: (none)
Example: clr # Clear the screen
All text is removed from the screen, resulting in an empty screen with the
cursor positioned in the upper left-hand corner.
#cmp
Command: cmp - compare two files
cmp [-ls] file1 file2
Flags: -l Loud mode. Print bytes that differ (in octal)
-s Silent mode. Print nothing, just return exit status
Examples: cmp file1 file2 # Tell whether the files are the same
cmp -l file1 file2 # Print all corresponding bytes that differ
Two files are compared. If they are identical, exit status 0 is returned.
If they differ, exit status 1 is returned. If the files cannot be opened, exit
status 2 is returned. If file1 is - , stdin is compared to file2.
#comm
Command: comm - print lines common to two sorted files
Syntax: comm [-123] file1 file2
Flags: -1 Suppress column 1 (lines only in file1)
-2 Suppress column 2 (lines only in file2)
-3 Suppress column 3 (lines in both files)
Examples: comm file1 file2 # Print all three columns
comm -12 file1 file2 # Print only lines common to both files
Two sorted files are read and compared. A three column listing is produced.
Files only in file1 are in column 1; files only in file2 are in column 2; files
common to both files are in column 3. The file name - means stdin.
#compress
Command: compress - compress a file using modified Lempel-Ziv coding
Syntax: compress [-cdfv] [file] ...
Flags: -c Put output on stdout instead of on file.Z
-d Decompress instead of compress
-f Force output even if there is no saving
-v Verbose mode
Examples: compress <infile >outfile # Compress 1 file
compress x y z # Compress 3 files to x.Z, y.Z, and z.Z
compress -d file.Z # Decompress file.Z to file
The listed files (or stdin, if none are given) are compressed using the
Ziv-Lempel algorithm. If the output is smaller than the input, the output is
put on file.Z or stdout if no files are listed. If compress is linked to
uncompress, the latter is the same as giving the -d flag. Similarly, a link to
zcat decompresses to stdout.
#cp
Command: cp - copy file
Syntax: cp file1 file2
cp file ... directory
Flags: (none)
Examples: cp oldfile newfile # Copy oldfile to newfile
cp file1 file2 /usr/ast # Copy two files to a directory
Cp copies one file to another, or copies one or more files to a directory.
A file cannot be copied to itself.
#cpdir
Command: cpdir - copy a directory and its subdirectories
Syntax: cpdir [-v] srcdir destdir
Flags: -v Verbose; cpdir tells what it is doing
Example: cpdir dir1 dir2 # Creat dir2 and copy dir1's files into it
Cpdir creates the target directory, goes into it, and copies all the files
in the source directory to it. When it is done, the target directory contains
the same files as the source directory. Subdirectories are copied recursively.
Links and special files are ignored.
#crc
Command: crc - print the checksum of the file data
Syntax: crc file ...
Flags: (none)
Example: crc *.c # Print checksums of all the C programs
The checksum of each argument is computed and printed, along with the file
length and its name, one file per lie. This program is useful for seeing if a
file transmitted to another machine has arrived correctly. It is conceptually
similar to sum, except that it uses a stronger checksum algorithm and also
prints the length.
#cron
Command: cron - clock daemon
Syntax: cron
Flags: (none)
Example: /usr/bin/cron # Use absolute path in /etc/rc
Cron is clock daemon. It is typically started up by including the command
/usr/bin/cron in the /etc/rc file. Once started, cron puts itself in the back-
ground, so no & is needed. It runs forever, sleeping most of the time. Once a
minute it wakes up and examines /usr/lib/crontab to see if there is any work to
do. If there is, the work is done. The entries of /usr/lib/crontab contain 6
elements each. Some examples follow:
min hr dat mo daycommand
* * * * * /usr/bin/date >/dev/tty0 #print date every minute
0 * * * * /usr/bin/date >/dev/tty0 #print date on the hour
30 4 * * 1-5 /bin/backup /dev/fd1 #do backup Mon-Fri at 0430
30 19 * * 1,3,5 /etc/backup /dev/fd1 #Mon, Wed, Fri at 1930
0 9 25 12 * /usr/bin/sing >/dev/tty0 #Xmas morning at 0900 only
#cut
Command: cut - select out columns of a file
Syntax: cut [-i] [-dc] [-farg]
cut [-carg]
Flags: -dc Change the column delimiter to c
-i Runs of delimiters count as one
Examples: cut -f2 file # Extract field 2
cut -c1-2,5 file # Extract character columns 1, 2, and 5
cut -c1-5,7- file # Extract all columns except 6
Cut extracts one or more fields or columns from a file and writes them on
standard output. If the -f flag is used, the fields are separated by a delim-
iter character, normally a tab, but can be changed using the -d flag. If the
-c flag is used, specific columns can be specified. The -f and -c flags are
mutually exclusive.
#date
Command: date - print or set the date and time
Syntax: date [[MMDDYY]hhmm[ss]]
Flags: -q Read the date from stdin
Examples: date # Print the date and time
date 0221921610 # Set date to Feb 21, 1992 at 4:10 p.m.
Without an argument, date prints the current date and time. With an argu-
ment, it sets the date and time. MMDDYY refers to the month, day, and year;
hhmmss refers to the hour, minute and second. Each of the six fields must be
exactly two digits.
#dd
Command: dd - disk dumper
Syntax: dd [option = value] ...
Flags: (none)
Examples: dd if=/dev/fd0 of=/dev/fd1 # Copy disk 0 to disk 1
dd if=x of=y bs=1w skip=4 # Copy x to y, skipping 4 words
dd if=x of=y count=3 # Copy three 512-byte blocks
This command is intended for copying partial files. The block size, skip
count, and number of blocks to copy can be specified. The options are:
if = file - Input file (default is stdin)
of = file - Output file (default is standard output)
ibs = n - Input block size (default 512 bytes)
obs = n - Output block size (default is 512 bytes)
bs = n - Block size; sets ibs and obs (default is 512 bytes)
skip = n - Skip n input blocks before reading
seek = n - Skip n output blocks before writing
count = n - Copy only n input blocks
conv = lcase - Convert upper case letters to lower case
conv = ucase - Convert lower case letters to upper case
conv = swab - Swap every pair of bytes
conv = noerror- Ignore errors and just keep going
Where sizes are expected, they are in bytes. However, the letters w, b, or k
may be appended to the number to indicate words (2 bytes), blocks (512 bytes),
or K (1024 bytes), respectively. When dd is finished, it reports the number of
full and partial blocks read and written.
#de
Command: de - disk editor
Syntax: de [-w] block_device
de -r file
Flags: -r Recover a file that has been removed
-w Enable writing, so device can be modified
Examples: de -r /usr/ast/prog.c # Undo the effects of: rm /usr/ast/prog.c
de -w /dev/fd0 # Edit /dev/fd0 for writing
De is a program for system administrators that allows disks to be inspected
block by block. A variety of display options and commands are available, as
described in /usr/doc/de.doc. For a summary, start the program and type h for
help. The program can also restore files that have just been removed by rm,
provided that the i-node and blocks are still intact. Another feature is
searching disks for ASCII strings, to help locate things after a crash.
Finally, individual disk words can be changed, for example, the sizes of block
special files.
#df
Command: df - report on free disk space and i-nodes
Syntax: df special ...
Flags: (none)
Examples: df /dev/ram # Report on free RAM disk space
df /dev/fd0 /dev/fd1 # Report on floppy disk space
df # Report on all mounted devices
The amount of disk space and number of i-nodes, both free and used is
reported.
#dhrystone
Command: dhrystone - integer benchmark
Syntax: dhrystone
Flags: (none)
Example: dhrystone # Run the dhrystone benchmark
Many years ago, a floating-point benchmark called whetstone was popular for
benchmarking FORTRAN programs. Nowadays, an integer benchmark called dhrystone
is widely used for benchmarking UNIX systems. This is it. Be warned, however,
that dhrystone is entirely CPU bound, and goes blindingly fast on machines with
high-speed caches. Although this is a good measure for programs that spend
most of their time in some inner loop, it is a poor benchmark for I/O bound
applications.
#diff
Command: diff - print differences between two files
Syntax: diff file1 file2
Flags: (none)
Example: diff file1 file2 # Print differences between 2 files
Diff compares two files and generates a list of lines telling how the two
files differ. Lines may not be longer than 128 characters.
#dis88
Command: dis88 - disassembler
Syntax: dis88 [-o] infile [outfile]
Flags: -o List the object code along with the assembly code
Examples: dis88 a.out >listing # Disassemble a.out
dis88 -o a.out listing # Ditto, but with object code
Dis88 is an 8088 disassembler. It takes an executable file and prints the
symbolic assembly code that corresponds to it. If the executable file contains
a symbol table (added by the program ast), the symbol table information is used
to give a more readable asembly listing.
#diskcheck
Command: diskcheck - check a disk for bad sectors
Syntax: diskcheck device start count
Flags: (none)
Examples: diskcheck /dev/at0 0 1200 # Check 1.2 MB floppy
diskcheck /dev/at0 100 50 # Check blocks 100 to 149
Diskcheck checks a disk for bad sectors by reading in each sector, writing a
known bit pattern onto it, reading it back in and comparing with what was writ-
ten. This check is then done a second time. Bad sectors are reported. After
each sector is tested, the original sector is restored.
#dosdir
Command: dosdir - list an MS-DOS directory
Syntax: dosdir [-lr] drive
Flags: -l Long listing
-r Recursively descend and print subdirectories
Examples: dosdir -l A # List root directory on drive A
dosdir -r C x/y # Recursively list directory x/y
Dosdir reads standard IBM PC diskettes or hard disk partitions in MS-DOS
format and lists their contents on standard output. Directory names should
contain slashes to separate components, even though MS-DOS uses backslashes.
The names dosdir, dosread, and doswrite are all links to the same program. The
program sees which function to perform by seeing how it was called. A drive
code of A causes the program to use /dev/dosA, typically a link to /dev/fd0.
Similarly, to have hard disk partition 1 be DOS drive C, /dev/dosC should be a
link to /dev/hd1, and so on for other drive codes.
#dosread
Command: dosread - read a file from an MS-DOS diskette
Syntax: dosread
Flags: -a ASCII file
Examples: dosread C g/adv >adv # Read file g/adv from hard disk
dosread -a A prog.c >x # Read ASCII file prog.c from drive A
Dosread reads one MS-DOS file and writes it on standard output. The file
name must use slash, not backslash as a separator. ASCII files have the final
CTRL-Z stripped, and carriage return plus line feed are mapped to line feed
only, the usual MINIX convention. A drive code of A causes the program to use
/dev/dosA, typically a link to /dev/fd0. Similarly, to have hard disk parti-
tion 1 be DOS drive C, /dev/dosC should be a link to /dev/hd1, and so on for
other drive codes.
#doswrite
Command: doswrite - write a file onto an MS-DOS diskette
Syntax: doswrite [-a] drive file
Flags: -a ASCII file
Examples: doswrite A x/y <z # Write file z to disk as x/y
doswrite -a B f # Copy stdin to MS-DOS file f
Doswrite writes its stdin to an MS-DOS file. The diskette or partition must
be formatted and have an MS-DOS file system already in place, including all the
directories leading up to the file. A drive code of A causes the program to
use /dev/dosA, typically a link to /dev/fd0. Similarly, to have hard disk par-
tition 1 be DOS drive C, /dev/dosC should be a link to /dev/hd1, and so on for
other drive codes.
#du
Command: du - print disk usage
Syntax: du [-s] dir
Flags: -s Summary only
Example: du dir # List disk space used by files in dir
Du examines a directory and prints the amount of space occupied by the files
in that directory and its subdirectories.
#echo
Command: echo - print the arguments
Syntax: echo [-n] argument ...
Flags: -n No line feed is output when done
Examples: echo Start Phase 1 # ``Start Phase 1'' is printed
echo -n Hello # ``Hello'' is printed without line feed
Echo writes its arguments to standard output. They are separated by blanks
and terminated with a line feed unless -n is present. This command is used
mostly in shell scripts.
#ed
Command: ed - editor
Syntax: ed file
Flags: (none)
Example: ed prog.c # Edit prog.c
Ed is functionally equivalent to the standard V7 editor, ed. It supports the
following commands:
(.) a: append
(.,.)c: change
(.,.)d: delete
e: edit new file"
f: print name of edited file"
(1,$)g: global command
(.) i: insert
(.,.+1)j: join lines together
(.) k: mark
(.) l: print with special characters in octal
(.,.)m: move
(.,.)p: print
q: quit editor"
(.) r: read in new file
(.,.)s: substitute
(1,$)v: like g, except select lines that do not match
(1,$)w: write out edited file
Many of the commands can take one or two addresses, as indicated above. The
defaults are shown in parentheses. Thus 'a' appends to the current line, and g
works on the whole file as default. The dot refers to the current line. Below
is a sample editing session with comments given following the # symbol.
ed prog.c # Edit prog.c
3,20p # Print lines 3 through 20
/whole/ # Find next occurence of whole
s/whole/while/ # Replace 'whole' by while
g/Buf/s//BUF/g # Replace Buf by BUF everywhere
w # Write the file back
q # Exit the editor
#elle
Command: elle - ELLE Looks Like Emacs
Syntax: elle file [file2]
Flags: (none)
Example: elle file.c # Start the editor
Elle is a screen-oriented editor that is patterned after Emacs. It can edit
multiple files, regardless of their length, can support 1 or 2 windows, and has
many other powerful features. An elle manual is present in /usr/doc/elle.doc.
#expand
Command: expand - convert tabs to spaces
Syntax: expand [-t1,t2, ...] [file]
Flags: -t Tab stop positions
Example: expand -16,32,48,64 # Expand stdin with tabs every 16 columns
Expand replaces tabs in the named files with the equivalent numbers of
spaces. If no files are listed, stdin is given. If only one tab is given, the
rest are multiples of it. The default is a tab every 8 spaces.
#expr
Command: expr - evaluate experession
Syntax: expr arg ...
Flags: (none)
Example: x=`expr + 1` # Add 1 to shell variable x
Expr computes the value of its argument and writes the result on standard
output. The valid operators, in order of increasing precedence, are listed
below. Operators grouped by {...} have the same precedence. Operators: |, &,
{<, <=, ==, !=, >=, >}, {+, -}, *.
Note that the V7 ":" operator is missing. Parentheses are permitted.
#factor
Command: factor - factor an integer less than 2**31
Syntax: factor number
Flags: (none)
Example: factor 450180 # Print the prime factors of 450180
Factor prints the prime factors of its argument in increasing order. Each
factor is printed as many times as it appears in the number.
#fdisk
Command: fdisk - partition a hard disk
Syntax: fdisk [-heads] [file]
Flags: -n Number of disk heads
Example: fdisk /dev/hd1 # Examine disk partitions
When fdisk starts up, it reads in the partition table and displays it. It
then presents a menu to allow the user to modify partitions, store the parti-
tion table on a file, or load it from a file. Partitions can be marked as
MINIX, DOS or other, as well as active or not. Using fdisk is self-
explanatory. However, be aware that repartitioning a disk may cause information
on it to be lost. Rebooting the system is mandatory after changing partition
sizes. MINIX, XENIX, PC-IX, and MS-DOS all have different ideas about how par-
titions are numbered. Be careful.
Furthermore, MINIX expects all partitions to begin on an even sector. The m
command, which marks a partition as MINIX, automatically rounds odd partitions
upward.
#fgrep
Command: fgrep - fast grep
Syntax: fgrep [-cfhlnsv] [file] [string] [file] ...
Flags: -c Count matching lines and only print count, not the lines
-f Take strings from file named in following argument
-h Omit file headers from printout
-l List file names once only
-n Each line is preceded by its line number
-s Status only, no output
-v Print only lines not matching
Examples: fgrep % prog.c # Print lines containing % sign
fgrep -f pattern prog.c # Take strings from pattern
Fgrep is essentially the same as grep, except that it only searches for
lines containing literal strings (no wildcard characters), and it is much fas-
ter.
#file
Command: file - make a guess as to a file's type based on contents
Syntax: file name ...
Flags: (none)
Example: file a.out ar.h # Guess at types
File reads the first block of a file and tries to make an intelligent guess
about what kind of file it is. It understands about archives, C source pro-
grams, executable binaries, shell scripts, and English text.
#find
Command: find - find files meeting a given condition
Syntax: find directory expression
Flags: (none)
Examples: find / -name a.out -print # Print all a.out paths
find /usr/ast ! -newer f -ok rm {} ;# Ask before removing
find /usr -size +20 -exec mv {} /big ;# move files > 20 blks
find / -name a.out -o -name `*.o` ) -exec rm {};# 2 conds
Find descends the file tree starting at the given directory checking each
file in that directory and its subdirectories against a predicate. If the
predicate is true, an action is taken. The predicates may be connected by -a
(Boolean and), -o (Boolean or) and ! (Boolean negation). Each predicate is
true under the conditions specified below. The integer n may also be +n to
mean any value greater than n, -n to mean any value less than n, or just n for
exactly n.
-name s true if current filename is s (include shell wild cards)
-size n true if file size is n blocks
-inum n true if the current file's i-node number is n
-mtime ntrue if modification time relative to today (in days) is n
-links ntrue if the number of links to the file is n
-newer ftrue if the file is newer than f
-perm n true if the file's permission bits = n (n is in octal)
-user u true if the uid = u (a numerical value, not a login name)
-grogp gtrue if the gid = g (a numerical value, not a group name)
-type x where x is bcdfug (block, char, dir, regular, setuid, setgid)
-xdev do not cross devices to search mounted file systems
Following the expression can be one of the following, telling what to do when a
file is found:
-print print the file name on standard output
-exec execute a MINIX command, {} stands for the file name
-ok prompts before executing the command
#fix
Command: fix - generate new file from old one and diff listing
Syntax: fix oldfile difflist >newfile
Flags: (none)
Example: fix old difflist >new # Generate new from old and diffs
Fix accepts a diff listing produced by diff and reconstructs the new file.
It is common for people to take a file, modify it, and then send the diff list-
ing between the old and new files to other people. Using fix, the old file,
and the diff listing, it is possible to creat the new file. For example:
diff oldfile newfile >difflist
fix oldfile difflist >new2
will generate a file new2 that is identical to newfile. A more sophisticated
alternative to fix is patch.
#fold
Command: fold - fold long lines
Syntax: fold [-n] [file] ...
Flags: -n How long should the output lines be
Examples: fold -60 # Fold stdin to 60 characters
fold -1 file # Fold file to 80 characters
Fold takes copies its input from the named file (or stdin, if none is speci-
fied) to standard output. However, lines longer than the given maximum length
(default 80) are broken into multiple lines of the maximum length by inserting
new line characters.
#fortune
Command: fortune - print a fortune
Syntax: fortune
Flags: (none)
Example: fortune # Print a fortune
Fortune picks a fortune at random from the fortunes file,
/usr/lib/fortune.dat, and prints it. This file consists of pieces of text
separated by a line containing only %%.
#from
Command: from - input half of a connection
Syntax: from port
Flags: (none)
Examples: from port | sort >x # Fetch and sort an incoming file
from abc | sh # Primitive sherver
To and from are used together to provide connection-oriented service. On
the sending machine, the last member of a pipeline is to port. On the receiving
machine, the first member of a pipe line is from port. The net result is that
the output of the sending pipeline goes into the input of the receiving pipe-
line, making pipelines work across the network.
#fsck
Command: fsck - perform file system consistency check
Syntax: fsck [-aclmrs] [device] ...
Flags: -a Automatically repair inconsistencies
-c Check and list only the specified i-nodes
-l List the files and directories in the filesytem
-m Make a new file system
-r Prompt user for repairs if inconsistencies are found
-s List the superblock of the file system
Examples: fsck /dev/hd4 # Check file system on /dev/hd4
fsck -a /dev/at0 # Automatically fix errors on /dev/at0
fsck -l /dev/fd0 # List the contents of /dev/fd0
fsck -c 2 3 /dev/hd3 # Check and list /dev/hd3 i-nodes 2 & 3
Fsck performs consistency checks on the file systems which reside on the
specified devices. It may also be used to list the contents of a file system or
to make a new file system. Fsck can be run from the initial menu and during
normal production. The default number of heads and sectors/track are built in
to the program (4 and 17, respectively). To change these, use ???. If they
are set wrong, fsck will give absurd errors.
#gather
Command: gather - gather up the files in a directory for transmission
Syntax: gather [-s] source_dir [-d] dest_dir [-b] bytes [-f] file
Flags: -b Desired number of bytes per output file
-d Destination directory
-f Base name of output files
-s Source directory
Examples: gather # Collect files in current dir into 60K archives
gather -d dir # Put the archives in dir
gather -b 90000 # Try to produce 90K archives
gather -s .. -d targ -b 90000# Try to produce 90K archives
It is often useful to collect all the files in a directory into one or more
archives for transmission by mail. This program collects all the files in the
source directory (default: current directory) and puts them into a shar
archive. The shar archive is then compressed and uuencoded. An attempt is
made to have the final .uue file be about the given size (default: 60K), but
since gather cannot really predict how much shar will add to the file, how much
compress will reduce the file, and how much uue will add again, the sizes can
fluctuate. If the -f file flag is given, the archives will be given the names
file_00.uue, file_01.uue etc. If -f is not given, the name of the source
directory is used as the base name.
#getlf
Command: getlf - wait until a line has been typed
Syntax: getlf [argument]
Flags: (none)
Example: getlf # Wait for a line
In shell scripts it is sometimes necessary to pause to give the user a
chance to perform some action, such as inserting a diskette. This command
prints its argument, if any, and then waits until a carriage return has been
typed, at which time it terminates. It is used in /etc/rc.
#grep
Command: grep - search a file for lines containing a given pattern
Syntax: grep [-ensv] pattern [file] ...
Flags: -e -e pattern is the same as pattern
-n Print line numbers
-s Status only, no printed output
-v Select lines that do not match
Examples: grep mouse file # Find lines in file containing mouse
grep [0-9] file # Print lines containing a digit
Grep searches one or more files (by default, stdin) and selects out all the
lines that match the pattern. All the regular expressions accepted by mined
are allowed. In addition, + can be used instead of * to mean 1 or more
occurrences, ? can be used to mean 0 or 1 occurrences, and | can be used
between two regular expressions to mean either one of them. Parentheses can be
used for grouping. If a match is found, exit status 0 is returned. If no
match is found, exit status 1 is returned. If an error is detected, exit
status 2 is returned.
#gres
Command: gres - grep and substitute
Syntax: gres [-g] pattern string [file] ...
Flags: -g Only change the first occurrence per line
Examples: gres bug insect # Replace bug with insect
gres ''^[A-Z]+$'' CAPS # Replace capital-only lines with CAPS
Gres is a poor man's sed. It looks for the same patterns as grep, and
replaces each one by the given string.
#head
Command: head - print the first few lines of a file
Syntax: head [-n] [file] ...
Flags: -n How many lines to print
Examples: head -6 # Print first 6 lines of stdin
head -1 file1 file2 # Print first line of two files
The first few lines of one or more files are printed. The default count is
10 lines. The default file is stdin.
#ic
Command: ic - integer calculator
Syntax: ic [expression]
Flags: (none)
Examples: ic # Start the calculator
ic 250 300+ # Start calculator with 550 on the stack
Ic is a reverse Polish notation calculator that works on 32-bit integers.
It starts out by computing the expression given as an argument, if any, and
then expects keyboard input. As an example, to compute ``23+5'' one first con-
verts this to reverse Polish, ``23 5+''. After the calculator starts, type
``23'' followed by a carriage return. Then type ``5'' and another carriage
return. Finally type ``+'' to see the result, 28 displayed on the stack.
Other operations work the same way. The calculator can use other radices for
input and output, and has registers that can be stored and loaded. The h com-
mand gives the help menu. See also /usr/doc/ic.doc.
#id
Command: id - print the uid and gid
Syntax: id
Flags: (none)
Example: id # Print the uid and gid
Id prints the current uid and gid, both numerically and symbolically. If
the effective uid and gid are different from the real ones, all of them are
printed.
#inodes
Command: inodes - print i-node information
Syntax: inodes
Flags: (none)
Example: inodes # Print information about inodes
Inodes expects a list of file names on stdin, one file name per line. For
each file named, the file type, mode, uid, gid, length, checksum, and and name
is printed. The checksum algorithm is the same as used by crc.
#kermit
Command: kermit - transfer a file using the kermit protocol
Syntax: kermit
Flags: (many)
Example: kermit # Start kermit
Kermit is a file transfer program, remote connection program, and much more.
Even summarizing it here would be out of the question. For a description of
it, see the 379 page book Kermit: A File Transfer Protocol by Frank da Cruz,
Digital Press, 1987, ISBN 0-932376-88-6, and also /usr/doc/kermit.doc.
#kill
Command: kill - send a signal to a process
Syntax: kill [-sig] process
Flags: -s Signal number to send
Examples: kill 35 # Send signal 15 to process 35
kill -9 40 # Send signal 9 to process 40
kill -2 0 # Send signal 2 to whole process group
A signal is sent to a given process. By default signal 15 (SIGTERM) is
sent. Process 0 means all the processes in the sender's process group.
#last
Command: last - display recent on-line session records
Syntax: last [-f file] [-r] [-n] [name] [tty] ...
Flags: -f Use file instead of /usr/adm/wtmp
-r Search backwards only to last reboot
-n Print a maximum of n lines
Examples: last reboot # When was the system last rebooted?
last ast # When was the last login for ast?
last -10 tty0 tty1 # Display last 10 logins on tty0 or tty1
Last Searches backward through the login administration file (default is
/usr/adm/wtmp), printing information about previous logins and reboots. During
a long search, the SIGQUIT signal (CTRL-\) causes last to display how far back
it has gone; it then continues.
#leave
Command: leave - warn when it is time to go home
Syntax: leave [ [+] hh[:]mm]
Flags: (none)
Examples: leave 1500 # Issue a warning at 2:55 p.m.:
leave 10:00 # Issue a warning at 9:55 a.m.
leave + 30 # Issue a warning in 25 minutes
Leave sets an alarm clock to a specified time and issues a warning 5 minutes
before, 1 minute before, and at the time to leave. It then keeps issuing warn-
ings every minute for 10 minutes, then quits. If no time is provided, the pro-
gram prompts for one.
#libpack
Command: libpack - pack an ASCII assembly code file
Syntax: libpack
Flags: (none)
Example: libpack <x.s >y.s # Pack x.s
This program is a filter that reads an ASCII assembly code file from stan-
dard input and writes the corresponding packed file on standard output. The
compiler libraries are archives of packed assembly code files.
#libupack
Command: libupack - convert a packed assembly code file to ASCII
Syntax: libupack
Flags: (none)
Example: libupack <y.s >x.s # Unpack y.s
This program is a filter that reads a packed assembly code file from stdin
and writes the corresponding ASCII file on standard output.
#ln
Command: ln - create a link to a file
Syntax: ln file [name]
Flags: (none)
Examples: ln file newname # Make newname a synonym for file
ln /usr/games/chess # Create a link called chess
A directory entry is created for name. The entry points to file. Hen-
ceforth, name and file can be used interchangeably. If name is not supplied,
the last component of file is used as the link name.
#login
Command: login - log into the computer
Syntax: login [user]
Flags: (none)
Example: login ast # Login as ast
Login allows a logged in user to login as someone else without first logging
out. If a password is needed, login will prompt for it.
#look
Command: look - look up words in dictionary
Syntax: look [-f] prefix[/suffix] [dictionary]
Flags: -f Fold upper case letters to lower case
Examples: look ard # Print words starting with ard
look /bing # Print words ending with bing
look -f f/ar # Print words starting with f, ending with ar
Look takes a prefix and/or suffix and searches /usr/lib/dictionary or the
specified dictionary for all words with that match. The words are printed.
The -f flag causes all upper case letters to be treated as lower case.
#lorder
Command: lorder - compute the order for library modules
Syntax: lorder file ...
Flags: (none)
Example: lorder proc1.s proc2.s # Give lorder information
Lorder accepts a series of packed or unpacked .s files and libraries, and
produces a partial ordering suitable for processing by tsort.
#lpr
Command: lpr - copy a file to the line printer
Syntax: lpr [file ...
Flags: (none)
Examples: lpr file & # Print file on the line printer
pr file | lpr & # Print stdin (pr's output)
Each argument is interpreted as a file to be printed. Lpr copies each file
to /dev/lp, without spooling. It inserts carriage returns and expands tabs.
Only one lpr at a time may be running.
#ls
Command: ls - list the contents of a directory
Syntax: ls [-ACFRadfgilrstuwx] name ...
Flags: -A All entries are listed, except . and ..
-C Multicolumn listing
-F Put / after directory names
-R Recursively list subdirectories
-a All entries are listed, even . and ..
-c Like -c except i-node change time used
-d Do not list contents of directories
-f List argument as unsorted directory
-g Group id given instead of user id
-i I-node number printed in first column
-l Long listing: mode, links, owner, size and time
-r Reverse the sort order
-s Give size in blocks (including indirect blocks)
-t Sort by time, latest first
-u Use last usage time instead of modification time
Examples: ls -l # List files in working directory
ls -lis # List with i-nodes and sizes
For each file argument, list it. For each directory argument, list its con-
tents, unless -d is present. When no argument is present, the working direc-
tory is listed.
#m4
Command: m4 - macro processor
Syntax: m4 [-D name = value] [-U name]
Flags: -D name = value Define a symbol
-U name Undefine a symbol
Example: m4 <m4test # Run M4
M4 is a general-purpose macro processor. It is described in /usr/doc direc-
tory. It has been used to implement programming languages, such as RATFOR.
#mail
Command: mail - send and receive electronic mail
Syntax: mail [pqr] [-f file] [user]
Flags: -f Use file instead of /usr/spool/mail/user as mailbox
-p Print all mail and then exit
-q Quit program if SIGINT received
-r Reverse print order, i.e., print oldest first
Examples: mail ast # Send a message to ast
mail # Read your mail
Mail is an extremely simple electronic mail program. It can be used to send
or receive email on a single MINIX system, in which case it functions as user
agent and local delivery agent. If the MAILER is defined in mail.c, it can
also call a transport agent to handle remote mail as well.
When called by user with no arguments, it examines the mailbox
/usr/spool/mail/user, prints one message (depending on the -r flag), and waits
for one of the following commands:
<newline> Go to the next message
- Print the previous message
!command Fork off a shell and execute command
CTRL-D Update the mailbox and quit (same as q)
d Delete the current message and go to the next one
q Update the mailbox and quit (same as CTRL-D)
p Print the current message again
s [file] Save message in the named file
x Exit without updating the mailbox
To send mail, the program is called with the name of the recipient as an
argument. The mail is sent, along with a postmark line containing the date.
For local delivery, a file named after the recipient in the directory
/usr/spool/mail must be writable.
#make
Command: make - a program for maintaining large programs
Syntax: make [-f file] [-ikns] [option] ... [target]
Flags: -f Use file as the makefile
-i Ignore status returned by commands
-n Report, but do not execute
-p Print macros and targets
-q Question up-to-dateness of target
-r Rule inhibit; do not use default rules
-s Silent mode
-t Touch files instead of making them
Examples: make kernel # Make kernel up to date
make -n -f file # Tell what needs to be done
Make is a program that is normally used for developing large programs con-
sisting of multiple files. It keeps track of which object files depend on
which source and header files. When called, it does the minimum amount of
recompilation to bring the target file up to date.
The file dependencies are expected in makefile or Makefile, unless another
file is specified with -f. Make has some default rules built in, for example,
it knows how to make .s files from .c files. Here is a sample makefile.
d=/user/ast # d is a macro
program: head.s tail.s# program depends on these
cc -o program head.s tail.s# tells how to make program
echo Program done. # announce completion
head.s: $d/def.h head.c # head.s depends on these
tail.s: $d/var.h tail.c # tail.s depends on these
A complete description of make would require too much space here. For more
information, see Feldman (1979). Many books on UNIX also discuss make.
#man
Command: man - display manual page
Syntax: man [man_directory] [digit] [name] ...
Flags: (none)
Examples: man # Display main index
man cdiff # Display man page for cdiff(1)
man 2 fork # Display man page for fork(2)
man 3 # Display the part 3 man pages
Man is a program that displays manual pages. When called with a program
name, it displays the manual page for that program. When the digit k is given
as an argument, the file /usr/man/mank is used instead of the default,
/usr/man/man1. When no name is given (or just a digit), the list of valid
entries is displayed. The arrows can be used to select an entry, and <return>
can be used to display the selected entry. Q or q leaves the program. A
directory name can be given to override the use of /usr/man.geordi@seas.ucla.edu (George T. Sinclair III) (12/19/89)
please change the address : lcc.minix@seas.ucla.edu to: lcc!minix@seas.ucla.edu thanks geordi