[comp.os.os9] TOP Infos, 2nd Part

ud@mutec.UUCP (Ulrich Dessauer) (10/07/88)

In article <339@infovax.lan.informatik.tu-muenchen.dbp.de> ocker@lan.informatik.tu-muenchen.dbp.de (Wolfgang Ocker) writes:
>
>Another long mail from Avygdor Moise has arrived. Here my comments
>(about UUCP, Mail, OXM, ls, documentation, ... Ulli will write some
>comments concerning the csh (again :-)).
>
Ok, here ut comes :-) :
~ 1. Your shell is called CSH, I presume is stands for C-Shell. The
~    intention of the folks who wrote the original C-Shell (csh) was (and
~    is) to provide an interactive (and batch) oriented command
~    interpreter that has capabilities normally available through the
~    use of the C language, like flow control, string manipulation and
~    arithmetic evaluation. Aliases and history are secondary to the
~    C-Shell (though they are a very important pleasant addition).
	Yes, you are right, I called it csh because of the UNIX(tm)
C-Shell. BUT I wrote this to add these features I missed in the OSK
shell. And it not is designed for scripts (BTW I hate shell scripts,
they are slow, using a lot of CPU time etc.). The things I missed
mostly had been aliasing, history and the '^' operator.

~ >~ 
~ >~ 4.  CSH should allow users to CHD to directories which are write
~ >~     protected but not read or execute protected.
~ >
~ >I think, this is a problem of the chdir() call.  The OS9 shell doesn't
~ >allow this (still compatible :-), too. 
~ 
~ This is a problem with the way the shell invokes chdir(). I patch my SHELL and
~ changed the mode from being READ|WRITE to READ (3->1). Now I can change
~ directory to directories that do not have write access.
	I am using the standard call in the C-library and this one seems
to call chdir () with READ+WRITE.

~ >~ 
~ >~ 5.  CSH should allow the addition of "." in the PATH list to facilitate
~ >~     execution of programs from current working directory (not shell
~ >~     scripts).
~ >
~ >In the current version csh scans through the execution directory, the
~ >PATH environment and then looks in the data directory.  If a file exist
~ >with the name of the desired program, csh tries to read the first two
~ >bytes if these are the module header sync bytes.  If this is true the
~ >program will be started, otherwise it is handled as a shell script.  If
~ >the first character in the script is an '*' then it is given to the OS9
~ >shell. 
~ 
~ I like the fact that your CSH will start an object file from the current
~ data directory. However, it is useful to have the ability to instruct
~ that command interpreter to first look in the current data directory
~ before searching elswhere, especially when one does development work in
~ "." and "." is changing frequently.
	Hmm, as an idea: Set the PATH to all directories you use and alias
the `chd` command to `chd \!*;chx $cwd`.

U//i

P.S.: Our new e-mail address is "...!altnet!altger!top".
-- 
UUCP:	..!unido!mutec!ud	ud@mutec.UUCP
Snail:	Ulrich Dessauer
	Markt&Technik Verlag AG, Hans-Pinsel-Strasse 2, D-8013 Haar
Voice:	+49 89 4613 745 (Office)