Bash variables: Difference between revisions
From wikinotes
| Line 3: | Line 3: | ||
<source lang="bash"> | <source lang="bash"> | ||
var="var" | var="var" | ||
FOO=${VARIABLE:=default} | FOO=${VARIABLE:=default} # FOO=$VARIABLE if exists, otherwise "default" | ||
read -n 1 input # user input to $input | read -n 1 input # user input to $input | ||
Revision as of 13:41, 17 July 2021
Assignment
var="var" FOO=${VARIABLE:=default} # FOO=$VARIABLE if exists, otherwise "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.
