Operator usage in bash shell

Common Bash comparisons

Operator Meaning Example

-z	Zero-length string	[ -z "$myvar" ]
-n	Non-zero-length string	[ -n "$myvar" ]
=	String equality	[ "abc" = "$myvar" ]
!=	String inequality	[ "abc" != "$myvar" ]
-eq	Numeric equality	[ 3 -eq "$myinteger" ]
-ne	Numeric inequality	[ 3 -ne "$myinteger" ]
-lt	Numeric strict less than	[ 3 -lt "$myinteger" ]
-le	Numeric less than or equals	[ 3 -le "$myinteger" ]
-gt	Numeric strict greater than	[ 3 -gt "$myinteger" ]
-ge	Numeric greater than or equals	[ 3 -ge "$myinteger" ]
-f	Exists and is regular file	[ -f "$myfile" ]
-d	Exists and is directory	[ -d "$mydir" ]
-nt	First file is newer than second one	[ "$myfile" -nt ~/.bashrc ]
-ot	First file is older than second one	[ "$myfile" -ot ~/.bashrc ]