w64devkit/man/man1/pgrep.1

.TH PGREP 1 2026-10-19 "w64devkit" "w64devkit Manual"
.SH NAME
pgrep, pkill \- find or signal processes by name
.SH SYNOPSIS
.B pgrep
.RB [ \-lvx ]
.I pattern
.br
.B pgrep
.RB [ \-lvx ]
.B \-P
.I ppid
.RI [ pattern ]
.br
.B pkill
.RB [ \-\c
.IR signal ]
.RB [ \-evx ]
.I pattern
.br
.B pkill
.RB [ \-\c
.IR signal ]
.RB [ \-evx ]
.B \-P
.I ppid
.RI [ pattern ]
.br
.B pkill \-l
.SH DESCRIPTION
.B pgrep
writes the process ID of each running process whose name matches
.IR pattern ,
one per line, on standard output.
.B pkill
instead sends each such process a signal,
.B TERM
by default.
Neither selects its own process.
.PP
.I pattern
is an extended regular expression, as in
.BR "grep \-E" ,
and matches case-sensitively anywhere in the name unless
.B \-x
is given.
With
.BR \-P ,
a process must also be a child of
.IR ppid ,
.I pattern
is optional, and operands after the first are ignored.
Without
.BR \-P ,
exactly one
.I pattern
is required.
.PP
Processes are visited in the order Windows lists them, not sorted by
process ID.
.SS Process names
Only the name of a process is matched, never its command line.
The name is the file name of its executable as Windows reports it,
including the extension, such as
.BR explorer.exe ,
truncated to 31 bytes.
A process running the same build of busybox is named after its applet
instead, such as
.B sh
or
.BR sleep ,
and a script whose
.B #!\&
line names an applet may be named after the script file.
The kit's command launchers, such as
.B sh.exe
and
.BR pgrep.exe ,
appear under their own names, each alongside the busybox process it
started.
.SH OPTIONS
Options may be grouped, as in
.BR \-lx ,
and the argument of
.B \-P
may be attached, as in
.BR \-P1234 .
Options may follow
.IR pattern ,
unless
.B POSIXLY_CORRECT
is set.
.B \-\-
ends the options, so that a
.I pattern
may begin with
.BR \- .
.TP
.BI \- signal
Send
.I signal
instead of
.BR TERM .
Only
.B pkill
accepts it, and only as the first argument.
.I signal
is a name, in any case and with or without a
.B SIG
prefix, or a number from 0 to 22.
The names are those listed by
.BR "pkill \-l" :
.BR HUP ,
.BR INT ,
.BR QUIT ,
.BR ILL ,
.BR FPE ,
.BR KILL ,
.BR SEGV ,
.BR PIPE ,
.BR TERM ,
and
.BR ABRT ,
plus
.B EXIT
for 0.
Signal 0, and a number without a name, select processes but send
nothing.
See
.B NOTES
for what the signals do on Windows.
.TP
.B \-l
For
.BR pgrep ,
write each process's name after its ID, separated by a space.
For
.BR pkill ,
write the signal numbers and names on standard output and exit without
signaling anything.
.TP
.B \-v
Negate the match: select the processes that would otherwise not be
selected.
With both
.B \-P
and
.IR pattern ,
a process is selected if its parent is not
.I ppid
or its name does not match.
.TP
.B \-x
Require
.I pattern
to match the whole name.
Since names include the extension,
.B pgrep \-x explorer
does not match
.BR explorer.exe .
.TP
.BI "\-P " ppid
Select only children of the process
.IR ppid ,
a non-negative decimal integer.
.TP
.B \-e
For
.BR pkill ,
write a line
.IB name " killed (pid " pid )
on standard output for each selected process, even when the signal was
not delivered.
.B pgrep
accepts
.B \-e
and ignores it.
.TP
.B \-\-help
As the first argument, print a usage message on standard output and
exit.
.SH ENVIRONMENT
.TP
.B BB_GLOBBING
Unless it is
.BR 0 ,
the wildcards
.B *
and
.B ?\&
in arguments are expanded as file names before the command sees them,
even inside quotes, so a
.I pattern
such as
.B vim.*\&
may be replaced by file names, as when run from
.BR cmd.exe .
A busybox process started with it unset sets it to
.B 0
for its children, so commands run from the kit's shell receive their
arguments as the shell expanded them.
.TP
.B POSIXLY_CORRECT
If set, even to an empty value, the first operand ends the options.
.PP
Variables that affect every busybox applet are described in
.BR busybox (1).
.SH EXIT STATUS
.TP
.B 0
At least one process was selected, or
.B pkill \-l
or
.B \-\-help
was given.
.B pkill
exits 0 even when a signal could not be delivered.
.TP
.B 1
No process was selected, or an error such as an invalid option,
.IR ppid ,
or regular expression.
Selecting only process 0,
.BR "[System\ Process]" ,
also exits 1.
.PP
A
.B pkill
that selects process 0 signals itself; see
.BR NOTES .
.SH EXAMPLES
List Vim processes with their names:
.PP
.RS 4
.EX
$ pgrep \-l vim
.EE
.RE
.PP
Terminate every instance of a program, and show what was signaled:
.PP
.RS 4
.EX
$ pkill \-e \-x \(aqserver\e.exe\(aq
server.exe killed (pid 12704)
server.exe killed (pid 16776)
.EE
.RE
.PP
Terminate a 32-bit program from a 64-bit busybox, which requires
.BR KILL :
.PP
.RS 4
.EX
$ pkill \-KILL \-x \(aqserver32\e.exe\(aq
.EE
.RE
.PP
List the children of the current shell:
.PP
.RS 4
.EX
$ sleep 60 &
[1] 22068
$ pgrep \-l \-P $$
22068 sleep
.EE
.RE
.PP
Check whether a program is running:
.PP
.RS 4
.EX
$ pgrep \-x \(aqgdb\e.exe\(aq >/dev/null && echo running
.EE
.RE
.SH NOTES
Differences from the procps commands and from busybox on Linux:
.IP \(bu 2
There is no
.BR \-a ,
.BR \-f ,
.BR \-n ,
.BR \-o ,
or
.BR \-s ,
which busybox has on Linux, nor
.BR \-i ,
.BR \-u ,
or the other procps options.
.IP \(bu 2
Names include the extension, and matching is case-sensitive although
Windows file names are not.
A bracket expression such as
.B [Nn]otepad
matches either case.
.IP \(bu 2
Errors exit with status 1, the same as no match, not 2 or 3.
.PP
Every process on the system is listed, including those of other users
and system processes such as
.BR System .
A process whose parent has exited has parent ID 1, unless Windows has
since reused the parent's ID, in which case it appears to be a child of
the process now holding that ID.
.B pkill
silently fails to signal a process it cannot open.
.PP
Windows has no signals, so
.B pkill
emulates them as
.BR kill (1)
does.
.B KILL
calls
.BR TerminateProcess ,
and any other signal that is sent makes the process call
.B ExitProcess
from a thread injected into it.
No signal handler runs either way, and
.B INT
does not send Ctrl+C.
The exit code of the process is the signal number shifted left 24 bits,
such as
.B 0x0F000000
for
.BR TERM ,
which the kit's shell reports as 128 plus the signal number.
.B pkill
does not wait for the process to exit.
Injecting a thread works only when the process and busybox are both
32-bit or both 64-bit, so otherwise only
.B KILL
takes effect.
Only the selected process is signaled, not its children.
.PP
Process 0,
.BR "[System\ Process]" ,
is listed first, and a
.B pkill
that selects it signals itself and its descendants in its place, as
.BR kill (1)
does for PID 0.
Unless the signal is 0 or a number without a name,
.B pkill
then ends as if by that signal, and may not signal the processes after
it.
A pattern such as
.B ss
or
.B o
matches
.BR "[System\ Process]" ,
and
.B \-v
with most other patterns selects it.
.PP
Each command excludes only its own process.
When started through the kit's
.B pgrep.exe
or
.B pkill.exe
launcher, as from
.BR cmd.exe ,
the launcher is not excluded, so a
.B pkill
whose pattern matches
.B pkill.exe
signals its own launcher.
.SH SEE ALSO
.BR busybox (1),
.BR grep (1),
.BR kill (1),
.BR killall (1),
.BR pidof (1),
.BR ps (1)