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Bash_test_expressions Cheat Sheet

A Software › Linux cheat sheet in English by andrsrz

Test command expressions

Programming Bash Linux Shell
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File Expres­sions

file1 -ef file2
file1 and file2 have the same inode numbers (the two filenames refer to the same file by hard linking).
file1 -nt file2
file1 is newer than file2.
file1 -ot file2
file1 is older than file2.
-b file
file exists and is a block-­special (device) file.
-c file
file exists and is a charac­ter­-sp­ecial (device) file.
-d file
file exists and is a directory.
-e file
file exists.
-f file
file exists and is a regular file.
-g file
file exists and is set-gr­oup-ID.
-G file
file exists and is owned by the effective group ID.
-k file
file exists and has its "­sticky bit" set.
-L file
file exists and is a symbolic link.
-O file
file exists and is owned by the effective user ID.
-p file
file exists and is a named pipe.
-r file
file exists and is readable (has readable permission for the effective user).
-s file
file exists and has a length greater than zero.
-S file
file exists and is a network socket.
-t fd
fd is a file descriptor directed to/from the terminal. This can be used to determine wheter standard input/­out­put­/error is being redire­cted.
-u file
file exists and is setuid.
-w file
file exists and is writable (has write permission for the effective user).
-x file
file exists and is executable (has execut­e/s­earch permission for the effective user).

Logical Expres­sions

AND
-a
OR
-o
NOT
!

Integer Expres­sions

integer1 -eq integer2
integer1 is equal to integer2.
integer1 -ne integer2
integer1 is not equal to integer2.
integer1 -le integer2
integer1 is less than or equal to integer2.
integer1 -lt integer2
integer1 is less than integer2.
integer1 -ge integer2
integer1 is greater than or equal to integer2.
integer1 -gt integer2
integer1 is greater than integer2.

String Expres­sions

string
string is not null.
-n string
The length of string is greater than zero.
-z string
The length of string is zero.
string1 = string2
string1 == string2
string1 and string2 are equal.
string1 != string2
string1 and string2 are not equal.
string1 > string2
string1 sorts after string2.
string1 < string2
string1 sorts before string2.

Modern Version of test

Instead of using [ expression ] is going to be [[ expression ]] and one designed for integers is (( expression )).

With [[ expression ]] we can have an expression matching a regular expres­sion:
string =~ regex.

For the integers in this way we can use the conven­tional way of other progra­mming languages expres­sions like:
int == 0.
int < 0.
int > 0.
int % 0.

And of course the logical operators, instead of using the older options of test we can use:
&& for and.
|| for or.
! for not.

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