Quick Tip

Master `diff` with Process Substitution for Inline Comparisons

Challenge: You need to compare two files or the output of two commands side-by-side, but you want to see the differences clearly without creating temporary files.

The Solution: Use process substitution with the `diff` command.

diff <(command1) <(command2)

Why it works: Process substitution (`<(…)` and `>(…)`) allows the output of a command to be treated as a file. `diff` then compares these “pseudo-files” directly, displaying any differences.

Pro-Tip: This technique is also incredibly useful for comparing the output of different versions of a configuration file or the results of two slightly modified commands.

Linux Tips & Tricks | © ngelinux.com | 5/14/2026