Test command

From Linux Shell Scripting Tutorial - A Beginner's handbook

The test command is used to check file types and compare values. Test is used in conditional execution. It is used for:

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

[edit] test command syntax

test condition

OR

test condition && true-command

OR

test condition || false-command

OR

test condition && true-command || false-command

Type the following command at a shell prompt (is 5 greater than 2? ):

test 5 > 2 && echo "Yes"
test 1 > 2 && echo "Yes"

Sample Output:

Yes
Yes

Rather than test whether a number is greater than 2, you have used redirection to create an empty file called 2 (see shell redirection). To test for greater than, use the -gt operator (see numeric operator syntax):

test 5 -gt 2 && echo "Yes"
test 1 -gt 2 && echo "Yes"

Yes

You need to use the test command while make decision. Try the following examples and note down its output:

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

[edit] See also

• Perform arithmetic operations
• Numeric comparison