Touch Access And Modify Times Individually

When running the touch command on an existing file:

$ touch README.md

The Access and Modify times of that file will be updated to the current time.

You can update these values individually with the -a and -m flags.

To update just the access time:

$ touch -a README.md

To update just the modify time:

$ touch -m README.md

See man touch for more details.