When I type this in the terminal
test 4 -lt 6
I don't get any output. Why not? I need that 0 or 1
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3Wouldn't it be nice if 'test' had an option to output a value immediately? Just the option. That's all we'd need.Todd Walton– Todd Walton2018-09-06 13:48:08 +00:00Commented Sep 6, 2018 at 13:48
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4 Answers
You get 0 or 1. In the exitcode.
bash-4.2$ test 4 -lt 6
bash-4.2$ echo $?
0
bash-4.2$ test 4 -gt 6
bash-4.2$ echo $?
1
Update: To store the exitcode for later use, just assign it to a variable:
bash-4.2$ test 4 -lt 6
bash-4.2$ first=$?
bash-4.2$ test 4 -gt 6
bash-4.2$ second=$?
bash-4.2$ echo "first test gave $first and the second $second"
first test gave 0 and the second 1
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2is there a way to pipe the exit code?indieman– indieman2012-10-11 07:38:49 +00:00Commented Oct 11, 2012 at 7:38
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5No. Only output can be redirected. Anyway, usually there is no need for that. To store it for later use, just assign it to a variable. Or tell us what exactly is your intention with that value.manatwork– manatwork2012-10-11 07:41:37 +00:00Commented Oct 11, 2012 at 7:41
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2The exit code is placed into the
$?variable -- at least until it gets overwritten by the next command you execute.Shadur-don't-feed-the-AI– Shadur-don't-feed-the-AI2012-10-11 07:45:21 +00:00Commented Oct 11, 2012 at 7:45 -
2PS: You can use the
$PIPESTATUSarray to get the result of multiple commands in a pipeline.$?will by be the result of the last command in the pipeline if thepipefailoption is off (the default).l0b0– l0b02012-10-11 09:26:29 +00:00Commented Oct 11, 2012 at 9:26 -
@indieman, if what you need is to do something else based on the exit status, you don't even need to save it—just use
if test 4 -lt 6; then echo test succeeeded; else echo test failed; fiWildcard– Wildcard2016-10-27 18:57:25 +00:00Commented Oct 27, 2016 at 18:57
Another way is
test 4 -lt 6 && echo 1 || echo 0
But be careful in that case. If test returns success and echo 1 fails echo 0 will be executed.
If you want the result of a comparison on standard out instead of an exit code, you can use the expr(1) command:
$ expr 4 '<=' 6
1
Two things to note:
- you will likely need to quote the operator as a lot of them conflict with shell metacharacters
- the output value is the opposite of the return code for
test.testreturns 0 for true (which is the standard for exit codes), butexprprints 1 for true.
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23. There is a
testshell builtin, which is considerably faster (about 50 times on my machine) than thetestandexprexecutables from the coreutils package.manatwork– manatwork2012-10-11 11:18:22 +00:00Commented Oct 11, 2012 at 11:18 -
+1 for the second point. Could get a bug that is very frustrating to find if you mess that up.Emanuel Berg– Emanuel Berg2012-10-11 17:18:33 +00:00Commented Oct 11, 2012 at 17:18
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Related to @manatwork's comment: Is
testa builtin or program (on superuser.com)Marc.2377– Marc.23772024-10-11 03:54:59 +00:00Commented Oct 11, 2024 at 3:54
You may type in the following command:
echo $(test -e myFile.txt) $?
