xmodmap

Swap left-click and right-click on the pointer

$ xmodmap -e 'pointer = 3 2 1'

$ xmodmap -e 'keycode [keycode] = [keyname]'

$ xmodmap -e 'keycode [keycode] ='

$ xmodmap [path/to/file]

xmodmap [options] [filename]

xmodmap modifies keymaps and pointer button mappings in X Window System. It can remap keys, swap modifier keys, and change mouse button behavior.
Common uses include swapping Caps Lock and Control, remapping special keys, or configuring multi-button mice. Changes are stored in memory and persist until the X session ends.

-e _expression_

Execute the given expression

Print current modifier map

Print current keymap table

Print current pointer map

Print expression grammar

Verbose output

Show what would be done without applying

Changes are not persistent across X server restarts. For permanent changes, add xmodmap commands to ~/.xinitrc or ~/.xprofile. Use xev to find keycodes. Modern systems may prefer setxkbmap for keyboard configuration.

xev(1), setxkbmap(1), xkbcomp(1)