How to check if a file exists in bash

Last updated on February 9, 2021 by Dan Nanni

When you are working on a shell script in bash, there are cases where you want to check if a particular file exists (or does not exist) in a directory, and then perform an action based on the condition. In bash, there are several ways to check whether or not a file exists in bash. In the following I demonstrate several bash shell script examples for this use case.

Check if File Exists in bash

The easiest way to check if a file exists is to use the test command. With -f <file-name> option, the test command returns true if the specified file exists.

FILE=/etc/pam.conf
if test -f $FILE; then
    echo "$FILE exists"
fi

Alternatively, you can use the bash's built-in flag -f, which can check for existence of a file when used inside bash's conditional expressions.

FILE=/etc/pam.conf
if [ -f $FILE ]; then
    echo "$FILE does not exists"
fi

It is also possible to use the following shorthand one-liner, where the conditional check and a corresponding action are written in a single line.

test -f $FILE && echo "$FILE exists."

[ -f $FILE ] && echo "$FILE exists."

Check if File Does Not Exist in bash

If you want to check if a file does not exist in bash, you can simply add ! in the above conditional expressions.

FILE=/etc/xmodulo.com

# Option 1
if ! test -f $FILE; then
    echo "$FILE does not exist"
fi

# Option 2
if [ ! -f $FILE ]; then
    echo "$FILE does not exist"
fi

# Option 3
test ! -f $FILE && echo "$FILE does not exist."

# Option 4
[ ! -f $FILE ] && echo "$FILE does not exist."

Check if Any File with Extension Exists in bash

In all previous bash script examples, the name of the file to check is pre-determined and known. What if you want to check if any file with a pattern (e.g., with a particular extension) exists? In that case, the name of file(s) to check for is not known. Note that the test command and the bash's -f flag do not work with wildcard patterns.

The easiest way to check if any file with a wildcard expression exists is to use ls command. You simply check if ls (with a pattern) returns non-zero.

PATTERN="/etc/systemd/*.conf"

if ls $PATTERN 1> /dev/null 2>&1; then
    echo "Files exist"
fi

Another method is to use the compgen command. You can use the -G option to specify a glob pattern. Simlar to ls, compgen returns a list of files that are matched.

PATTERN="/etc/systemd/*.conf"

if compgen -G $PATTERN > /dev/null; then
    echo "Files exist"
fi

The following shorthand one-liners are also possible.

ls $PATTERN 1> /dev/null 2>&1 && echo "Files exist"

compgen -G $PATTERN > /dev/null && echo "Files exist"

If you find this tutorial helpful, I recommend you check out the series of bash shell scripting tutorials provided by Xmodulo.

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