The condition types
that you can use with the test command fall into three types:
string
comparison,
arithmetic
comparison,
and file
conditionals.
String Comparison
Result
string1 = string2 True if the
strings are equal
string1 != string2 True if the
strings are not equal
-n string True if the string is
not null
-z string True if the string is
null (an empty string)
Arithmetic Comparison
Result
expression1 -eq expression2 True
if the expressions are equal
expression1 -ne expression2 True
if the expressions are not equal
expression1 -gt expression2 True
if expression1 is greater than expression2
expression1 -ge expression2 True
if expression1 is greater than or equal to
expression2
expression1 -lt expression2 True
if expression1 is less than expression2
expression1 -le expression2 True
if expression1 is less than or equal to
expression2
! expression True if the
expression is false, and vice versa
File Conditional
Result
-d file True if the file is a
directory
-e file True if the file exists.
Note that historically the -e option
has not been portable, so -f is
usually used.
-f file True if the file is a
regular file
-g file True if set-group-id is
set on file
-r file True if the file is
readable
-s file True if the file has
nonzero size
-u file True if set-user-id is
set on file
-w file True if the file is
writable
-x file True if the file is
executable