Bash touch Command - Change File Timestamps

Using the touch Command

The touch command is used to change file timestamps or create an empty file if it doesn't exist.

It's often used to create placeholder files or update timestamps for build systems.

Basic Usage

To update the access and modification times of a file, use touch filename:

touch file.txt

Options

The touch command has options to change how it works:

• -a - Update only the access time
• -m - Update only the modification time
• -t - Set the timestamp to a specific time
• -c - Do not create any files

-a Option: Change Access Time

The -a option lets you update the access time of a file.

touch -a file.txt

-m Option: Change Modification Time

The -m option lets you update only the modification time of a file.

ls -l
-rw-r--r-- 1 user 197609 208 Apr  9 06:24 my_file.txt
touch -m my_file.txt
ls -l
-rw-r--r-- 1 user 197609 208 Apr  9 08:25 my_file.txt

-t Option: Set Specific Timestamp

The -t option allows you to set the timestamp to a specific time.

ls -l
-rw-r--r-- 1 user 197609 208 Apr  9 06:24 my_file.txt
touch -t 202501010000 my_file.txt
ls -l
-rw-r--r-- 1 user 197609 208 Jan  1 00:00 my_file.txt

-c Option: Do Not Create Files

The -c option tells touch not to create any files if they do not exist.

This is useful when you want to update timestamps without accidentally creating new files.

touch -c non_existent_file.txt

Using touch with Wildcards

Wildcards allow you to update timestamps on multiple files at once.

For example, touch *.txt will update the timestamps of all text files in the directory.

touch *.txt