Bash Quick Start Guide

Using temporary files cleanly

If you need a temporary file in your script to store data for the script's run, it can be tempting to assume a fixed path for the file in /tmp:

# Store the current date for later# Requires GNU/BSD `date` with non-POSIX %s formatdate +%s > /tmp/myscript-timestamp

/tmp exists on virtually all Unix systems, which makes it a popular choice. However, this approach has some risks:

• There may be a safer or more suitable location for temporary files specified by the system, or preferred by the user, such as /var/tmp. The /tmp directory might be very strictly locked down in some environments, especially PCI-DSS-compliant systems.
• If the temporary filename name is not unique, and more than one instance of the script runs ...