odin@ucscb.UCSC.EDU (Jon Granrose) (12/15/89)
I am looking for a program that will cat a file backwards. Not with all the letters reversed but one that prints the last line, then the second to last line, 3 from the last line, etc.) If it doesn't exist then I will write my own but I thought I'd ask first. Thanks Jon -- _____________________________________________________________________________ |Jon Granrose |ARPA: odin@ucscb.UCSC.EDU jonathan@sco.com | // Only | |Cowell College, UCSC| 74036.3241@compuserve.com |\X/ Amiga!| |Santa Cruz, CA 95064|UUCP:..!ucbvax!ucscc!ucscb!odin Bitnet:odin@ucscb.bitnet| | "Remember! No matter where you go, there you are." - B. Banzai | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
falk@peregrine.Sun.COM (Ed Falk) (12/16/89)
> >I am looking for a program that will cat a file backwards. Not with all the >letters reversed but one that prints the last line, then the second to last >line, 3 from the last line, etc.) If it doesn't exist then I will write my >own but I thought I'd ask first. The unix tail(1) command will do it.
karl@MorningStar.Com (Karl Fox) (12/16/89)
In article <6488@lindy.Stanford.EDU> odin@ucscb.UCSC.EDU (Jon Granrose) writes:
I am looking for a program that will cat a file backwards. Not with all the
letters reversed but one that prints the last line, then the second to last
line, 3 from the last line, etc.) If it doesn't exist then I will write my
own but I thought I'd ask first.
Try this:
#!/bin/sh
grep -n "^" $* | sort -rn -t: | cut -d: -f2-
--
Karl Fox, Morning Star Technologies karl@MorningStar.COMbill@twwells.com (T. William Wells) (12/16/89)
In article <6488@lindy.Stanford.EDU> odin@ucscb.UCSC.EDU (Jon Granrose) writes:
: I am looking for a program that will cat a file backwards. Not with all the
: letters reversed but one that prints the last line, then the second to last
: line, 3 from the last line, etc.) If it doesn't exist then I will write my
: own but I thought I'd ask first.
Try: nl | sort -nr | cut (you figure the arguments). I would not
be surprised to find that this is as fast as a "tailored" program.
(Why? Because the disk access pattern of the sort *might* be
better than that of a file reverser.)
---
Bill { uunet | novavax | ankh | sunvice } !twwells!bill
bill@twwells.com" Maynard) (12/16/89)
In article <6488@lindy.Stanford.EDU> odin@ucscb.UCSC.EDU (Jon Granrose) writes: >I am looking for a program that will cat a file backwards. Not with all the >letters reversed but one that prints the last line, then the second to last >line, 3 from the last line, etc.) If it doesn't exist then I will write my >own but I thought I'd ask first. It's probably pretty simple to do in C, but here's a quick and dirty in awk I use to insure that my disks get unmounted in the reverse order of being mounted: awk '{ lines[NR] = $0 } END { for(i=NR; i>=1; i--) print lines[i]; }' <file It's not the fastest in the world, and it's limited by awk's available memory, but it does the job... -- Jay Maynard, EMT-P, K5ZC, PP-ASEL | Never ascribe to malice that which can jay@splut.conmicro.com (eieio)| adequately be explained by stupidity. {attctc,bellcore}!texbell!splut!jay +---------------------------------------- Here come Democrats...here come Democrats...throwing money a-way...
merlyn@iwarp.intel.com (Randal Schwartz) (12/16/89)
In article <6488@lindy.Stanford.EDU>, odin@ucscb (Jon Granrose) writes: | I am looking for a program that will cat a file backwards. Not with all the | letters reversed but one that prints the last line, then the second to last | line, 3 from the last line, etc.) If it doesn't exist then I will write my | own but I thought I'd ask first. Don't write your own... get Perl... perl -e 'print reverse(<>);' Simple, eh? Just another Perl hacker, -- /== Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ====\ | on contract to Intel's iWarp project, Hillsboro, Oregon, USA, Sol III | | merlyn@iwarp.intel.com ...!uunet!iwarp.intel.com!merlyn | \== Cute Quote: "Welcome to Oregon... Home of the California Raisins!" ==/
tomm@voodoo.UUCP (Tom Mackey) (12/16/89)
In article <6488@lindy.Stanford.EDU> odin@ucscb.UCSC.EDU (Jon Granrose) writes: >I am looking for a program that will cat a file backwards. Not with all the >letters reversed but one that prints the last line, then the second to last >line, 3 from the last line, etc.) If it doesn't exist then I will write my >own but I thought I'd ask first. >Thanks >Jon >-- > _____________________________________________________________________________ >|Jon Granrose |ARPA: odin@ucscb.UCSC.EDU jonathan@sco.com | // Only | >|Cowell College, UCSC| 74036.3241@compuserve.com |\X/ Amiga!| >|Santa Cruz, CA 95064|UUCP:..!ucbvax!ucscc!ucscb!odin Bitnet:odin@ucscb.bitnet| >| "Remember! No matter where you go, there you are." - B. Banzai | >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I am going to post the source and manpage for tac to alt.sources. I suspect that many will send you the source, but I haven't seen it posted lately. If you don't get alt.sources, and still want it, let me know and I'll try exercising our mailer. -- Tom Mackey (206) 234-7767 (wk) Boeing Computer Services ....uw-beaver!ssc-vax!voodoo!tomm M/S 6M-17, P.O. Box 24346, Seattle, WA 98124-0346
6600pete@hub.UUCP (12/16/89)
From article <6488@lindy.Stanford.EDU>, by odin@ucscb.UCSC.EDU (Jon Granrose): > I am looking for a program that will cat a file backwards. Not with all the > letters reversed but one that prints the last line, then the second to last > line, 3 from the last line, etc.) If it doesn't exist then I will write my > own but I thought I'd ask first. ...and the fourth answer... TAIL(1) USER COMMANDS TAIL(1) NAME tail - display the last part of a file SYNOPSIS tail +|-number [ lbc ] [ fr ] [ filename ] OPTIONS r Copy lines from the end of the file in reverse order. The default for r is to print the entire file in reverse order. ------------------------------------------------------------------------------- Pete Gontier | InterNet: 6600pete@ucsbuxa.ucsb.edu, BitNet: 6600pete@ucsbuxa Editor, Macker | Online Macintosh Programming Journal; mail for subscription Hire this kid | Mac, DOS, C, Pascal, asm, excellent communication skills
roy@comcon.UUCP (Roy M. Silvernail) (12/16/89)
In article <3324@hub.UUCP>, 6600pete@hub.UUCP writes: > From article <6488@lindy.Stanford.EDU>, by odin@ucscb.UCSC.EDU (Jon Granrose): > > I am looking for a program that will cat a file backwards. Not with all the > > letters reversed but one that prints the last line, then the second to last > > line, 3 from the last line, etc.) If it doesn't exist then I will write my > > own but I thought I'd ask first. > > ...and the fourth answer... > > TAIL(1) USER COMMANDS TAIL(1) > Hmmm... at this site, not quite: tail -r data usage: tail [+/-[n][lbc][f]] [file] man tail man: tail not found ah, well.... I don't have to reverse files very often:-) -- _R_o_y _M_. _S_i_l_v_e_r_n_a_i_l | UUCP: uunet!comcon!roy | "No, I don't live in an igloo!" [ah, but it's my account... of course I opine!] -Sourdough's riposte SnailMail: P.O. Box 210856, Anchorage, Alaska, 99521-0856, U.S.A., Earth, etc.
emv@math.lsa.umich.edu (Edward Vielmetti) (12/17/89)
I mailed this to Jon but I haven't seen it here yet. 'tac', from 4.3 BSD contrib, author is Jay Lepreau. didn't we have this discussion a few weeks ago? Perhaps this is something for 'Frequently Answered Questions.'. --Ed
guy@auspex.UUCP (Guy Harris) (12/19/89)
>...and the fourth answer...
Which isn't correct:
auspex% tail -r /etc/termcap > /tmp/stuff
auspex% ls -lL /tmp/stuff /etc/termcap
-rw-rw-r-- 1 root 133962 Jul 14 14:39 /etc/termcap
-rw-r--r-- 1 guy 32768 Dec 18 13:01 /tmp/stuff
32768 != 133962. "tail -r" doesn't reverse the *entire* file, just a
chunk at the end, in the UNIX versions I know of:
BUGS
Data for a tail relative to the end of the file is stored in
a buffer, and thus is limited in size.