Bash compare a command output to string

Question

Output is same, and it always echos need to pull. If I remove the quotes around $text in if condition it throws the too many arguments error.

var="$(git status -uno)" && 

text="On branch master Your branch is up-to-date with 'origin/master'. nothing to commit (use -u to show untracked files)"; 

echo  $var; 
echo  $text; 
if [ "$var" = "$text" ]; then
    echo "Up-to-date"
else
    echo "need to pull"
fi

The output of `git status` is not a single line of text. In general, this is a very brittle approach to scripting git – there is no guarantee that the output of `git status` doesn't change between git versions. A better approach would be using `git status --porcelain` (see [docs](https://git-scm.com/docs/git-status#Documentation/git-status.txt---porcelainltversiongt)). — Benjamin W., Mar 29 '19 at 20:54
When I issue `git status -uno` against an up to date branch the return from `git status` has line feeds in it. Those don't seem to be accounted for in your `$text` variable. — JNevill, Mar 29 '19 at 20:54

Gilles Quénot · Accepted Answer · 2020-07-24T10:05:20.617

17

Better do this, =~ for bash regex :

#!/bin/bash

var="$(git status -uno)" 

if [[ $var =~ "nothing to commit" ]]; then
    echo "Up-to-date"
else
    echo "need to pull"
fi

or

#!/bin/bash

var="$(git status -uno)" 

if [[ $var == *nothing\ to\ commit* ]]; then
    echo "Up-to-date"
else
    echo "need to pull"
fi

edited Jul 24 '20 at 10:05

answered Mar 29 '19 at 20:54

Gilles Quénot

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[tag:bash] *regex* is performance killer! – F. Hauri - Give Up GitHub Mar 30 '19 at 07:47
New script is quicker – Gilles Quénot Mar 30 '19 at 11:01
What does =~ mean? – Anu Shibin Joseph Raj Jul 24 '20 at 06:10
Post edited accordingly – Gilles Quénot Jul 24 '20 at 10:05

F. Hauri - Give Up GitHub · Answer 2 · 2021-09-11T08:22:09.013

4

Warning: bash's regex require more ressources and won't work in other shell!

Simple old fashion

This syntax is POSIX compatible, not bash only!

if LANG=C git status -uno | grep -q up-to-date ; then
    echo "Nothing to do"
else
    echo "Need to upgrade"
fi

Or testing a variable (posix too)

From this answer to How to check if a string contains a substring in Bash, here is a compatible syntax, working under any standard POSIX shell:

#!/bin/sh

stringContain() { [ -z "${2##*$1*}" ] && { [ -z "$1" ] || [ -n "$2" ] ;} ; }

var=$(git status -uno)

if  stringContain "up-to-date" "$var" ;then
    echo "Up-to-date"
    # Don't do anything
else
    echo "need to pull"
    # Ask for upgrade, see: 
fi

edited Sep 11 '21 at 08:22

answered Mar 29 '19 at 20:56

F. Hauri - Give Up GitHub

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Closing the question as a duplicate (with the dupehammer, nonetheless) *and* answering it is a bit odd, no? – Benjamin W. Mar 29 '19 at 22:38
@BenjaminW. I agree, it was late, I answered spontaneously, then I realized: title of quest stand for *output of a command*, but question itsefl is about a *variable check"... – F. Hauri - Give Up GitHub Mar 30 '19 at 07:45

Bash compare a command output to string

2 Answers2

Simple old fashion

Or testing a variable (posix too)