Cheat Sheet #day49 - touch

touch Command Cheatsheet

The touch command in Unix/Linux is used primarily to create empty files or update the access and modification times of existing files. Below are the basic and advanced usages of the touch command along with practical examples.

Basic Usage

• Create an empty file

    touch filename
  

• Create multiple empty files

    touch file1 file2 file3
  

• Update the timestamp of an existing file

    touch filename
  

Common Options

• Change only the access time

    touch -a filename
  

• Change only the modification time

    touch -m filename
  

• Use a specific date and time

    touch -t [[CC]YY]MMDDhhmm[.ss] filename
  

• Reference another file's timestamps

    touch -r reference_file filename
  

• Do not create files (only change timestamps)

    touch -c filename
  

Examples

• Create a single empty file

    touch file.txt
  

• Create multiple empty files

    touch file1.txt file2.txt file3.txt
  

• Update the timestamp of an existing file

    touch existing_file.txt
  

• Change only the access time

    touch -a file.txt
  

• Change only the modification time

    touch -m file.txt
  

• Set a specific date and time

    touch -t 202406302359.59 file.txt
  

• Reference another file's timestamps

    touch -r reference_file.txt target_file.txt
  

• Do not create files if they do not exist

    touch -c file.txt
  

Advanced Usage

• Create a file with a specific timestamp

    touch -t 202406302359.59 file.txt
  

• Use the current time as the timestamp

    touch -d "now" file.txt
  

• Set the timestamp to a specific date using -d

    touch -d "2023-06-30 23:59:59" file.txt
  

Practical Tips

• Creating Empty Files: Use touch to quickly create placeholder files or to create files required by scripts or applications.

• Updating Timestamps: Use touch to update the access or modification times of files without modifying their contents.

• Setting Specific Timestamps: Use the -t or -d options to set specific timestamps, which can be useful for testing or when working with log files.

Quick Reference

• Create an empty file:

    touch filename
  

• Update access time:

    touch -a filename
  

• Update modification time:

    touch -m filename
  

• Set specific date and time:

    touch -t [[CC]YY]MMDDhhmm[.ss] filename
  

• Reference another file's timestamps:

    touch -r reference_file filename
  

• Do not create files:

    touch -c filename
  

This cheatsheet covers the essential commands and options for using touch effectively, from creating empty files to updating and setting specific timestamps. Adjust the commands according to your specific requirements and environment.