Explain Usage Of The Linux Left Bracket /usr/bin/[ Command
Q. I see [ command in /usr/bin directory. What is the /usr/bin/[ command used for?
A.This is test command and it is used to check file types and compare values.
General syntax is as follows:
[ EXPRESSION ]
For example, find out if /etc/passwd exists or not:
[ -f /etc/passwd ] && echo "Yes" || echo "No"
Regularly you write it as follows:
if [ -f /etc/passwd ] then echo "Yes" else echo "No" fi
OR
if test -f /etc/passwd then echo "Yes" else echo "No" fi
Read test or [ command man page for all other expressions.
man [
man test
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Tags: /usr/bin/[, expression, expressions, left bracket, linux command, shell check file types, shell compare values, test command, [ ~ Last updated on: May 5, 2008
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