The /tmp directory contains mostly files that are required temporarily, it is used by different programs to create lock files and for temporary storage of data. Many of these files are important for currently running programs and deleting them may result in a system crash.

Why is tmp used in Linux?

In Unix and Linux, the global temporary directories are /tmp and /var/tmp. Web browsers periodically write data to the tmp directory during page views and downloads. Typically, /var/tmp is for persistent files (as it may be preserved over reboots), and /tmp is for more temporary files.

Is it safe to delete tmp in Linux?

/tmp is needed by programs to store (temporary) information. It’s not a good idea to delete files in /tmp while the system is running, unless you know exactly which files are in use and which are not. /tmp can (should) be cleaned during a reboot.