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25,287
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command-line
bash
scripts
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🔍 See Original Answer on Ask Ubuntu ⧉ 🔗
URL:
https://askubuntu.com/q/1182804
Title:
Why combine commands on a single line in a Bash script?
ID:
/2019/10/21/Why-combine-commands-on-a-single-line-in-a-Bash-script_
Created:
October 21, 2019
Edited: October 23, 2019
Upload:
September 15, 2024
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Why we sometimes like to use it
When we are writing answers here in Ask Ubuntu it is helpful to put them into one line which people can cut and paste into their terminal easier. For example:
$ CurrDir=$PWD ; cd /bin ; ls -la dd ; cd "$CurrDir"
-rwxr-xr-x 1 root root 72632 Mar 2 2017 dd
As mentioned earlier you could use && for the same effect but if there were errors above you could end up on the wrong directory. In this case ; is preferable to && that isn’t tested for success:
rick@alien:~/askubuntu$ CurrDir=$PWD && cd /bin && llllssss -la dd && cd "$CurrDir"
llllssss: command not found
rick@alien:/bin$
Why we have to use it
There are some commands where you have to string multiple lines together. One case is the abbreviated if-commands-fi which must be one line. For example:
$ [[ 2 -eq 2 ]] && { echo 2 equals 2 ; echo setting three to 3 ; three=3 ; }
2 equals 2
setting three to 3