Conditional expression

The test command is used to check file types and compare values. You can also use [ as test command. It is used for:

• File attributes comparisons
• Perform string comparisons.
• Arithmetic comparisons.

Syntax

[ condition ]

OR

[ ! condition ]

OR

[ condition ] && true-command

OR

[ condition ] || false-command

OR

[ condition ] && true-command || false-command

Examples

[ 5 == 5 ] && echo "Yes" || echo "No"
[ 5 == 15 ] && echo "Yes" || echo "No"
[ 5 != 10 ] && echo "Yes" || echo "No"
[ -f /etc/resolv.conf ] && echo "File /etc/resolv.conf found." || echo "File /etc/resolv.conf not found."
[ -f /etc/resolv1.conf ] && echo "File /etc/resolv.conf found." || echo "File /etc/resolv.conf not found."