# set > Toggle shell options or set the values of positional parameters. > More information: . - Display the names and values of shell variables: `set` - Export newly initialized variables to child processes: `set -a` - Write formatted messages to `stderr` when jobs finish: `set -b` - Write and edit text in the command line with `vi`-like keybindings (e.g. `yy`): `set -o {{vi}}` - Exit the shell when (some) commands fail: `set -e`