info > skill(1)

📌 NAME

skill, snice — send a signal or report process status

🚀 Quick Reference

Use Case	Command	Description
Send TERM signal to processes matching expression	skill [signal] expression	Default signal is TERM
Kill all processes on a PTY device	skill -KILL -t /dev/pts/*	Forcefully kill users on a terminal
Stop (pause) processes for multiple users	skill -STOP -u user1 -u user2	Stop specified users’ processes
Change process priority	snice +7 -c command	Slow down (or speed up) a command
List available signals	skill -l	Display all signal names
Simulate actions without effect	skill -n expression	No‑action mode for testing

📖 SYNOPSIS

skill [signal] [options] expression
snice [new priority] [options] expression

📝 DESCRIPTION

⚠️ These tools are obsolete and unportable. The command syntax is poorly defined. Consider using the killall, pkill, and pgrep commands instead.

The default signal for skill is TERM. Use -l or -L to list available signals. Particularly useful signals include HUP, INT, KILL, STOP, CONT, and 0. Alternate signals may be specified in three ways: -9 -SIGKILL -KILL.

The default priority for snice is +4. Priority numbers range from +20 (slowest) to -20 (fastest). Negative priority numbers are restricted to administrative users.

⚙️ OPTIONS

• -f, --fast — ⚡ Fast mode. This option has not been implemented.
• -i, --interactive — 🤔 Interactive use. You will be asked to approve each action.
• -l, --list — 📋 List all signal names.
• -L, --table — 🗂️ List all signal names in a nice table.
• -n, --no-action — 🧪 No action; perform a simulation of events that would occur but do not actually change the system.
• -v, --verbose — 🗣️ Verbose; explain what is being done.
• -w, --warnings — ⚠️ Enable warnings. This option has not been implemented.
• -h, --help — ❓ Display help text and exit.
• -V, --version — ℹ️ Display version information.

🔍 PROCESS SELECTION OPTIONS

Selection criteria can be: terminal, user, pid, command. The options below may be used to ensure correct interpretation.

• -t, --tty tty — The next expression is a terminal (tty or pty).
• -u, --user user — The next expression is a username.
• -p, --pid pid — The next expression is a process ID number.
• -c, --command command — The next expression is a command name.
• --ns pid — Match the processes that belong to the same namespace as pid.
• --nslist ns,... — list which namespaces will be considered for the --ns option. Available namespaces: ipc, mnt, net, pid, user, uts.

🚦 SIGNALS

The behavior of signals is explained in signal(7) manual page.

💡 EXAMPLES

snice -c seti -c crack +7

Slow down seti and crack commands.

skill -KILL -t /dev/pts/*

Kill users on PTY devices.

skill -STOP -u viro -u lm -u davem

Stop three users.

🔗 SEE ALSO

kill(1), kill(2), killall(1), nice(1), pkill(1), renice(1), signal(7)

📜 STANDARDS

No standards apply.

👤 AUTHOR

Albert Cahalan <albert AT users.net> wrote skill and snice in 1999 as a replacement for a non-free version.

🐛 REPORTING BUGS

Please send bug reports to <procps AT freelists.org>