Groups > linux.debian.user > #159259 > unrolled thread

Extract substring from cat

Started by	"Alfred Charles Stockton" <alf@devacs.za.net>
First post	2015-10-16 14:50 +0200
Last post	2015-10-17 03:40 +0200
Articles	10 — 10 participants

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  Extract substring from cat "Alfred Charles Stockton" <alf@devacs.za.net> - 2015-10-16 14:50 +0200
    Re: Extract substring from cat Nemeth Gyorgy <friczy@freemail.hu> - 2015-10-16 15:00 +0200
      Re: Extract substring from cat <tomas@tuxteam.de> - 2015-10-16 15:50 +0200
        Re: Extract substring from cat Kurt Flex <flxkrt@aol.com> - 2015-10-18 22:00 +0200
          Re: Extract substring from cat tomas@tuxteam.de - 2015-10-18 22:10 +0200
    Re: Extract substring from cat Darac Marjal <mailinglist@darac.org.uk> - 2015-10-16 15:10 +0200
    Re: Extract substring from cat Santiago Vila <sanvila@unex.es> - 2015-10-16 15:30 +0200
    Re: Extract substring from cat "John L. Cunningham" <djohngo@gmail.com> - 2015-10-16 15:30 +0200
    Re: Extract substring from cat Jonathan <winelauncher.jonathan@googlemail.com> - 2015-10-17 01:40 +0200
      Re: Extract substring from cat Cindy-Sue Causey <butterflybytes@gmail.com> - 2015-10-17 03:40 +0200

#159259 — Extract substring from cat

From	"Alfred Charles Stockton" <alf@devacs.za.net>
Date	2015-10-16 14:50 +0200
Subject	Extract substring from cat
Message-ID	<qkcCm-6zl-7@gated-at.bofh.it>

If I issue the command cat /etc/*-release on my Debian system I get:-

PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
NAME="Debian GNU/Linux"
VERSION_ID="8"
VERSION="8 (jessie)"
ID=debian
HOME_URL="http://www.debian.org/"
SUPPORT_URL="http://www.debian.org/support/"
BUG_REPORT_URL="https://bugs.debian.org/"

Now what I would like to do is to only print the substring "Debian
GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.

Please tell me how I should go about this?

--
Regards,
Alf Stockton

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#159260

From	Nemeth Gyorgy <friczy@freemail.hu>
Date	2015-10-16 15:00 +0200
Message-ID	<qkcM2-6LS-5@gated-at.bofh.it>
In reply to	#159259

2015-10-16 14:15 keltezéssel, Alfred Charles Stockton írta:
> 
> If I issue the command cat /etc/*-release on my Debian system I get:-
> 
> PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
> NAME="Debian GNU/Linux"
> VERSION_ID="8"
> VERSION="8 (jessie)"
> ID=debian
> HOME_URL="http://www.debian.org/"
> SUPPORT_URL="http://www.debian.org/support/"
> BUG_REPORT_URL="https://bugs.debian.org/"
> 
> Now what I would like to do is to only print the substring "Debian
> GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.
> 
> Please tell me how I should go about this?
> 
> --
> Regards,
> Alf Stockton
> 
> 
> 
cat /etc/*-release | grep ^PRETTY_NAME | sed 's/^.*=//'

-- 
--- Friczy ---
'Death is not a bug, it's a feature'

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#159264

From	<tomas@tuxteam.de>
Date	2015-10-16 15:50 +0200
Message-ID	<qkdyp-7XP-1@gated-at.bofh.it>
In reply to	#159260

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On Fri, Oct 16, 2015 at 02:54:25PM +0200, Nemeth Gyorgy wrote:
> 2015-10-16 14:15 keltezéssel, Alfred Charles Stockton írta:
> > 
> > If I issue the command cat /etc/*-release on my Debian system I get:-
> > 
> > PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
> > NAME="Debian GNU/Linux"
> > VERSION_ID="8"
> > VERSION="8 (jessie)"
> > ID=debian
> > HOME_URL="http://www.debian.org/"
> > SUPPORT_URL="http://www.debian.org/support/"
> > BUG_REPORT_URL="https://bugs.debian.org/"
> > 
> > Now what I would like to do is to only print the substring "Debian
> > GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.
> > 
> > Please tell me how I should go about this?
> > 
> > --
> > Regards,
> > Alf Stockton
> > 
> > 
> > 
> cat /etc/*-release | grep ^PRETTY_NAME | sed 's/^.*=//'

Many insightful answers have been given. Yours is an example of "useless
use of cat" [1], better spelt as

  grep ^PRETTY_NAME /etc/*-release | sed 's/^.*=//'

Even better, since sed can do grep:

  sed -ne '/^PRETTY_NAME=/ s/^.*=// p' < /etc/*-release

[1] <http://uselessuseofcat.com/>

regards
- -- t
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#159409

From	Kurt Flex <flxkrt@aol.com>
Date	2015-10-18 22:00 +0200
Message-ID	<ql2hA-6M1-7@gated-at.bofh.it>
In reply to	#159264

On Fri, Oct 16, 2015 at 03:14:31PM +0200, tomas@tuxteam.de wrote:
> On Fri, Oct 16, 2015 at 02:54:25PM +0200, Nemeth Gyorgy wrote:
> > 2015-10-16 14:15 keltezéssel, Alfred Charles Stockton írta:
> > cat /etc/*-release | grep ^PRETTY_NAME | sed 's/^.*=//'
> 
> Many insightful answers have been given. Yours is an example of "useless
> use of cat" [1], better spelt as
>
>   grep ^PRETTY_NAME /etc/*-release | sed 's/^.*=//'
> 
> Even better, since sed can do grep:
> 
>   sed -ne '/^PRETTY_NAME=/ s/^.*=// p' < /etc/*-release

Not if there may be more than one file matching the pattern. In that
case at least your "better" example breaks. It can be fixed by
omitting "<".


Kurt

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#159413

From	tomas@tuxteam.de
Date	2015-10-18 22:10 +0200
Message-ID	<ql2rg-7dt-15@gated-at.bofh.it>
In reply to	#159409

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On Sun, Oct 18, 2015 at 09:58:01PM +0200, Kurt Flex wrote:
> On Fri, Oct 16, 2015 at 03:14:31PM +0200, tomas@tuxteam.de wrote:
> > On Fri, Oct 16, 2015 at 02:54:25PM +0200, Nemeth Gyorgy wrote:
> > > 2015-10-16 14:15 keltezéssel, Alfred Charles Stockton írta:
> > > cat /etc/*-release | grep ^PRETTY_NAME | sed 's/^.*=//'
> > 
> > Many insightful answers have been given. Yours is an example of "useless
> > use of cat" [1], better spelt as
> >
> >   grep ^PRETTY_NAME /etc/*-release | sed 's/^.*=//'
> > 
> > Even better, since sed can do grep:
> > 
> >   sed -ne '/^PRETTY_NAME=/ s/^.*=// p' < /etc/*-release
> 
> Not if there may be more than one file matching the pattern. In that
> case at least your "better" example breaks. It can be fixed by
> omitting "<".

You are right, of course. Thanks :-)
- -- tomás
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#159261

From	Darac Marjal <mailinglist@darac.org.uk>
Date	2015-10-16 15:10 +0200
Message-ID	<qkcVJ-7cO-51@gated-at.bofh.it>
In reply to	#159259

[Multipart message — attachments visible in raw view] — view raw

On Fri, Oct 16, 2015 at 02:15:46PM +0200, Alfred Charles Stockton wrote:
> 
> If I issue the command cat /etc/*-release on my Debian system I get:-
> 
> PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
> NAME="Debian GNU/Linux"
> VERSION_ID="8"
> VERSION="8 (jessie)"
> ID=debian
> HOME_URL="http://www.debian.org/"
> SUPPORT_URL="http://www.debian.org/support/"
> BUG_REPORT_URL="https://bugs.debian.org/"
> 
> Now what I would like to do is to only print the substring "Debian
> GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.
> 
> Please tell me how I should go about this?

The EASY way? "( source /etc/*-release; echo $PRETTY_NAME )".

'source' executes the commands in the file(s) which, in this case, are 
simple variable assignments. 'echo' prints the contents of one of those 
variables. Finally "( ... ; ... )" executes the two commands one after 
the other in a subshell. When the subshell exits (after the echo 
command), the variables will be forgotten.

> 
> --
> Regards,
> Alf Stockton
> 
> 

-- 
For more information, please reread.

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#159262

From	Santiago Vila <sanvila@unex.es>
Date	2015-10-16 15:30 +0200
Message-ID	<qkdf5-7zE-33@gated-at.bofh.it>
In reply to	#159259

On Fri, Oct 16, 2015 at 02:15:46PM +0200, Alfred Charles Stockton wrote:
> Now what I would like to do is to only print the substring "Debian
> GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.

The standard says /etc/os-release is shell-compatible, so I would do this:

. /etc/os-release
echo ${PRETTY_NAME}

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#159263

From	"John L. Cunningham" <djohngo@gmail.com>
Date	2015-10-16 15:30 +0200
Message-ID	<qkdf5-7zE-51@gated-at.bofh.it>
In reply to	#159259

On Fri, Oct 16, 2015 at 02:15:46PM +0200, Alfred Charles Stockton wrote:
> 
> If I issue the command cat /etc/*-release on my Debian system I get:-
> 
> PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
> NAME="Debian GNU/Linux"
> VERSION_ID="8"
> VERSION="8 (jessie)"
> ID=debian
> HOME_URL="http://www.debian.org/"
> SUPPORT_URL="http://www.debian.org/support/"
> BUG_REPORT_URL="https://bugs.debian.org/"
> 
> Now what I would like to do is to only print the substring "Debian
> GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.
> 
> Please tell me how I should go about this?

$ gawk -F= '/^PRETTY/{ print $2 }' /etc/*-release

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#159287

From	Jonathan <winelauncher.jonathan@googlemail.com>
Date	2015-10-17 01:40 +0200
Message-ID	<qkmLo-4Eg-17@gated-at.bofh.it>
In reply to	#159259

On Fri, 16 Oct 2015 14:15:46 +0200
"Alfred Charles Stockton" <alf@devacs.za.net> wrote:

> Now what I would like to do is to only print the substring "Debian
> GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.
> 
> Please tell me how I should go about this?

lsb_release -ds
from lsb-release package.

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#159294

From	Cindy-Sue Causey <butterflybytes@gmail.com>
Date	2015-10-17 03:40 +0200
Message-ID	<qkoDv-7lZ-3@gated-at.bofh.it>
In reply to	#159287

On 10/16/15, Jonathan <winelauncher.jonathan@googlemail.com> wrote:
> On Fri, 16 Oct 2015 14:15:46 +0200
> "Alfred Charles Stockton" <alf@devacs.za.net> wrote:
>
>> Now what I would like to do is to only print the substring "Debian
>> GNU/Linux 8 (jessie)" from the 1st line, preferably in bash.
>>
>> Please tell me how I should go about this?
>
> lsb_release -ds
> from lsb-release package.

I've been partially playing along with this thread as it has evolved.
I received 2 slightly different outputs regarding this latest..

$ lsb_release -ds
$ Debian GNU/Linux unstable (sid)

and...

$ cat /etc/*-release
$ PRETTY_NAME="Debian GNU/Linux stretch/sid"

Unstable is certainly Sid's first, middle, and last name, grin.
Stretch nicely defines where Sid is in a release cycle of the
moment..... a nice little time stamp of sorts.... ish. :)

Cindy :)

-- 
Cindy-Sue Causey
Talking Rock, Pickens County, Georgia, USA

* runs with duct tape *

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csiph-web

Extract substring from cat

Contents

#159259 — Extract substring from cat

#159260

#159264

#159409

#159413

#159261

#159262

#159263

#159287

#159294