LinuxQuestions.org - [SOLVED] Sed: assigning its output to a variable.

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- - Sed: assigning its output to a variable. (https://www.linuxquestions.org/questions/linux-newbie-8/sed-assigning-its-output-to-a-variable-860606/)

stf92

02-03-2011 10:41 PM

Sed: assigning its output to a variable.

Kernel 2.6.21.5, GNU/Linux (Slackware 12.0).

Hi:
In this script,

Code:

semoi@darkstar:~$ cat rename4.sh

#!/bin/bash



INPUT="k3b_audio_0_04"

echo $INPUT | sed s/k3b_audio_0_// > OUTPUT

echo "Input=  $INPUT"

echo "Output= $OUTPUT"

semoi@darkstar:~$

I would like the output to be

Code:

$ Input=  k3b_audio_0_04

$ Output= 04

But how do I send sed's output into OUTPUT? Regards.

EDIT: I found it:
OUTPUT=$(echo $INPUT | sed s/k3b_audio_0_//)

lucmove

02-03-2011 10:52 PM

Code:

semoi@darkstar:~$ cat rename4.sh

#!/bin/bash



INPUT="k3b_audio_0_04"

OUTPUT=$(echo $INPUT | sed s/k3b_audio_0_//)

echo "Input=  $INPUT"

echo "Output= $OUTPUT"

You can also do this:

Code:

OUTPUT=`echo $INPUT | sed s/k3b_audio_0_//`

But backticks make the code look kind of "dirty", are much harder to escape if the code inside them also contains backticks, and they are not a subshell. The $(CODE) format is a lot cleaner, embeddable and it creates a subshell.

stf92

02-04-2011 12:04 AM

Yes. As you can see, I had figured out a way out minutes before you pressed 'Submit Reply'. The second form I'll bear it in mind, and the morals behind it. Thanks a lot.

grail

02-04-2011 12:38 AM

Or in this case you could have just used parameter substitution:

Code:

OUTPUT=${INPUT##*_}

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