SKILL

NAME

skill, snice - send a signal or report process status

SYNOPSIS

skill [signal to send] [options] process selection criteria
snice [new priority] [options] process selection criteria

DESCRIPTION

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

GENERAL OPTIONS

-f	fast mode	This is not currently useful.
-i	interactive use	You will be asked to approve each action.
-v	verbose output	Display information about selected processes.
-w	warnings enabled	This is not currently useful.
-n	no action	This only displays the process ID.
-V	show version	Displays version of program.

PROCESS SELECTION OPTIONS

Selection criteria can be: terminal, user, pid, command. The options below may be used to ensure correct interpretation. Do not blame Albert for this interesting interface.

-t	The next argument is a terminal (tty or pty).
-u	The next argument is a username.
-p	The next argument is a process ID number.
-c	The next argument is a command name.

SIGNALS

The signals listed below may be available for use with skill. When known, numbers and default behavior are shown.

Name	Num	Action	Description
0	0	n/a	exit code indicates if a signal may be sent
ALRM	14	exit
HUP	1	exit
INT	2	exit
KILL	9	exit	this signal may not be blocked
PIPE	13	exit
POLL		exit
PROF		exit
TERM	15	exit
USR1		exit
USR2		exit
VTALRM		exit
STKFLT		exit	may not be implemented
PWR		ignore	may exit on some systems
WINCH		ignore
CHLD		ignore
URG		ignore
TSTP		stop	may interact with the shell
TTIN		stop	may interact with the shell
TTOU		stop	may interact with the shell
STOP		stop	this signal may not be blocked
CONT		restart	continue if stopped, otherwise ignore
ABRT	6	core
FPE	8	core
ILL	4	core
QUIT	3	core
SEGV	11	core
TRAP	5	core
SYS		core	may not be implemented
EMT		core	may not be implemented
BUS		core	core dump may fail
XCPU		core	core dump may fail
XFSZ		core	core dump may fail

EXAMPLES

Command	Description
snice seti crack +7	Slow down seti and crack
skill -KILL -v /dev/pts/*	Kill users on new-style PTY devices
skill -STOP viro lm davem	Stop 3 users
snice -17 root bash	Give priority to root's shell

STANDARDS

No standards apply.

AUTHOR

Albert Cahalan <albert@users.sf.net> wrote skill and snice in 1999 as a replacement for a non-free version, and is the current maintainer of the procps collection. Please send bug reports to <procps-feedback@lists.sf.net>.