Bash variables: Difference between revisions
From wikinotes
| Line 12: | Line 12: | ||
<blockquote> | <blockquote> | ||
<source lang="bash"> | <source lang="bash"> | ||
test -z $var && echo "variable does not exist, or has no value" | test -z "$var" && echo "variable does not exist, or has no value" | ||
test -n $var && echo "variable exists and has a nonzero value" | test -n "$var" && echo "variable exists and has a nonzero value" | ||
</source> | </source> | ||
There are many more options. See <code>man test</code>. | There are many more options. See <code>man test</code>. | ||
</blockquote><!-- test variable --> | </blockquote><!-- test variable --> | ||
Revision as of 02:04, 17 July 2021
Assignment
var="var" FOO=${VARIABLE:=default} read -n 1 input # user input to $input
test variable
test -z "$var" && echo "variable does not exist, or has no value" test -n "$var" && echo "variable exists and has a nonzero value"There are many more options. See
man test.
