Groups | Search | Server Info | Login | Register

Groups > comp.unix.shell > #25973

a sed question

From Salvador Mirzo <smirzo@example.com>
Newsgroups comp.unix.shell, comp.unix.questions
Subject a sed question
Followup-To comp.unix.shell
Date 2024-12-18 16:46 -0300
Organization A noiseless patient Spider
Message-ID <874j304vv3.fsf@example.com> (permalink)

Cross-posted to 2 groups.

Followups directed to: comp.unix.shell

Show all headers | View raw

(*) Summary

I wrote a sed script that makes a line replacement after it finds the
right spot.  So far so good.  Then I added quit command after the
change, but the quit does not seem to take effect---violating my
expectation.  I'll appreciate any help on understanding what's going on.

(*) A detailed description

I wrote this program:

--8<-------------------------------------------------------->8---
%cat make-release
#!/bin/sh
usage()
{
  printf '%s tag file\n' $0
  exit 1
}
test $# '<' 2 && usage
tag="$1"
shift
sed "/<<Release>>=/ {
 n;
 c\\
$tag
}" $*
--8<-------------------------------------------------------->8---

Here's how I use it.  My objective with it is to replace that
/something/ in the text file with a new argument.

--8<-------------------------------------------------------->8---
%cat sample.txt 
Lorem ipsum dolor...

<<Release>>=
something
@ 

... sit a met [...]
%
--8<-------------------------------------------------------->8---

Here's how I invoke it:

--8<-------------------------------------------------------->8---
%sh make-release release1 sample.txt 
Lorem ipsum dolor...

<<Release>>=
release1
@ 

... sit a met [...]
--8<-------------------------------------------------------->8---

So far so good.  I decided to try it on longer files and I wanted to see
the change more quickly (without long files scrolling past my terminal),
so I decided to add a /q/ command right after the c commmand.  I
thought---it will make sed quit right after making the change, so I can
see it works as desired and then I remove the /q/ and release it to
production.  But that did not happen.

--8<-------------------------------------------------------->8---
%cat make-release
#!/bin/sh
usage()
{
  printf '%s tag file\n' $0
  exit 1
}
test $# '<' 2 && usage
tag="$1"
shift
sed "/<<Release>>=/ {
 n;
 c\\
$tag
q}" $*
--8<-------------------------------------------------------->8---

I still see the whole file:

--8<-------------------------------------------------------->8---
%sh make-release release1 sample.txt 
Lorem ipsum dolor...

<<Release>>=
release1
@ 

... sit a met [...]
%
--8<-------------------------------------------------------->8---

I failed the exercise I gave myself.  Can you help me to understand why
the q command isn't stopping sed as I thought it would?  I'd like to get
a better intuition.

I've been reading Dale Dougherty and Arnold Robin's ``sed & awk'' book.
If you have any recommended sed-related bibliography, I'd appreciate it,
too.

Back to comp.unix.shell | Previous | Next — Next in thread | Find similar

Thread

a sed question Salvador Mirzo <smirzo@example.com> - 2024-12-18 16:46 -0300
  Re: a sed question John-Paul Stewart <jpstewart@personalprojects.net> - 2024-12-18 15:12 -0500
  Re: a sed question Ralf Damaschke <rwspam@gmx.de> - 2024-12-19 01:14 +0000
    Re: a sed question Salvador Mirzo <smirzo@example.com> - 2024-12-19 09:05 -0300
      Re: a sed question Ralf Damaschke <rwspam@gmx.de> - 2024-12-20 00:55 +0000
        Re: a sed question gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-20 12:44 +0000
          Re: a sed question Ralf Damaschke <rwspam@gmx.de> - 2024-12-21 00:17 +0000
            Re: a sed question Kaz Kylheku <643-408-1753@kylheku.com> - 2024-12-21 03:09 +0000
              sed... (Was: a sed question) gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-21 03:36 +0000
                Re: sed... (Was: a sed question) Kaz Kylheku <643-408-1753@kylheku.com> - 2024-12-21 03:57 +0000
                Re: sed... (Was: a sed question) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-21 15:38 +0100
                Re: sed... (Was: a sed question) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-21 17:29 +0100
                Re: sed... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-21 14:23 -0800
                Re: sed... Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-22 00:33 +0100
                Re: sed... (Was: a sed question) Lars Poulsen <lars@cleo.beagle-ears.com> - 2024-12-21 21:46 +0000
                Re: sed... (Was: a sed question) Kaz Kylheku <643-408-1753@kylheku.com> - 2024-12-22 21:22 +0000
              Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-21 15:35 +0100
              Re: a sed question Ralf Damaschke <rwspam@gmx.de> - 2024-12-22 00:43 +0000
  Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-20 15:55 +0100
    Checking for right # of args in a shell script (Was: a sed question) gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-20 15:11 +0000
      Re: Checking for right # of args in a shell script (Was: a sed question) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-20 16:49 +0100
        Re: Checking for right # of args in a shell script (Was: a sed question) gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-20 17:43 +0000
    Re: a sed question Salvador Mirzo <smirzo@example.com> - 2024-12-21 09:17 -0300
      Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-21 16:19 +0100
        Re: a sed question Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-21 13:41 -0800
          Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-22 00:50 +0100
            Re: a sed question Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-21 16:26 -0800
              Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-22 01:41 +0100
            Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-22 00:31 +0000
              Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-22 02:06 +0100
      Re: a sed question Andy Walker <anw@cuboid.co.uk> - 2024-12-21 15:34 +0000
        Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-21 17:14 +0100
        Re: a sed question Salvador Mirzo <smirzo@example.com> - 2024-12-21 15:21 -0300
          Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-21 20:48 +0100
      Re: a sed question Helmut Waitzmann <nn.throttle@xoxy.net> - 2024-12-21 19:20 +0100
    Re: a sed question Ordatious <order@order.invalid> - 2024-12-22 09:19 +0000
      Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-22 19:23 +0100
  Re: a sed question Ed Morton <mortonspam@gmail.com> - 2024-12-21 08:13 -0600
    Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-21 21:09 +0000
      Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-22 01:02 +0100
        Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-22 00:28 +0000
          Re: a sed question Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-21 16:36 -0800
            Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-22 01:52 +0000
              Re: a sed question Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-21 21:09 -0800
                Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-22 05:56 +0000
                Re: a sed question Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-21 22:55 -0800
                Re: a sed question Eric Pozharski <apple.universe@posteo.net> - 2024-12-23 10:09 +0000
                Re: a sed question gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-23 12:41 +0000
                Re: a sed question Kaz Kylheku <643-408-1753@kylheku.com> - 2024-12-23 18:47 +0000
                Re: a sed question Eric Pozharski <apple.universe@posteo.net> - 2024-12-24 11:20 +0000
          Re: a sed question Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-22 02:22 +0100
      Re: a sed question gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-22 01:09 +0000
      Re: a sed question Kaz Kylheku <643-408-1753@kylheku.com> - 2024-12-22 20:03 +0000
      Re: a sed question Ed Morton <mortonspam@gmail.com> - 2024-12-23 07:26 -0600
        How to solve The Miracle (was Re: a sed question) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-12-23 21:09 +0100
        Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-23 22:57 +0000
          Re: a sed question Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-23 15:06 -0800
            Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-24 00:28 +0000
              Re: a sed question anthk <anthk@openbsd.home> - 2025-03-23 09:45 +0000
                Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-03-23 23:41 +0000
          Re: a sed question Ed Morton <mortonspam@gmail.com> - 2024-12-24 06:20 -0600
            Dealing with four-year-olds... (Was: a sed question) gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-24 12:58 +0000
            Re: a sed question Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-24 20:57 +0000
              Re: a sed question Kaz Kylheku <643-408-1753@kylheku.com> - 2024-12-24 21:46 +0000
                Arguing with a four-year-old (Was: a sed question) gazelle@shell.xmission.com (Kenny McCormack) - 2024-12-24 23:53 +0000

csiph-web