Often pidof is used in shell scripts in this form:
if pidof daemon >/dev/null; then
...
fi
The redirection to /dev/null is needed because otherwise the script
would output the found PIDs.
Let's add a -q option which, similary to grep, just sets the exit code.
Also exit on first match, as there is no reason to proceed further when
at least a process is matched.
Tested with:
$ ./pidof bash
17701 14019 5276 2967
$ echo $?
0
$ ./pidof bashx
$ echo $?
1
$ ./pidof -q bash
$ echo $?
0
$ ./pidof -q bashx
$ echo $?
1
Short separator option used 's' instead of 'S' which
meant it pidof would use the single-shot option when you
meant separator.
Added alias for -S using -d to give some sysvinit pidof
compatibility.
References:
commit 73492b182dprocps-ng/procps#141
pidof will miss scripts that are run a certain way due to how
they appear in procfs. This is just a note to say it might miss
them.
References:
procps-ng/procps#17
I frequency use pidof command with strace system call tracer.
strace can trace MULTIPLE processes specified with "-p $PID"
arguments like:
strace -p 1 -p 1030 -p 3043
Sometimes I want to do as following
strace -p $(pidof httpd)
However, above command line doesn't work because -p option
is needed for specifying a pid. pidof uses a whitespace as
a separator. For passing the output to strace, the separator
should be replaced with ' -p '.
This maybe not a special to my use case.
This commit introduces -S option that allows a user to specify a
separator the one wants.
$ ./pidof bash
./pidof bash
24624 18790 12786 11898 11546 10766 7654 5095
$ ./pidof -S ',' bash
./pidof -S ',' bash
24624,18790,12786,11898,11546,10766,7654,5095
$ ./pidof -S '-p ' bash
./pidof -S '-p ' bash
24624-p 18790-p 12786-p 11898-p 11546-p 10766-p 7654-p 5095
$ ./pidof -S ' -p ' bash
./pidof -S ' -p ' bash
24624 -p 18790 -p 12786 -p 11898 -p 11546 -p 10766 -p 7654 -p 5095
$ strace -p $(./pidof -S ' -p ' bash)
strace -p $(./pidof -S ' -p ' bash)
strace: Process 24624 attached
strace: Process 18790 attached
strace: Process 12786 attached
...
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
This commit introduces support for special %PPID value that
can be passed to the -o option as a substitution for parent
PID. It also allows users to use two additional separators
for omitted PIDs - colon and semicolon.
As the sysvinit becomes obsolete, some of the bundled tools
need to find a new home. The procps-ng project seems to be
the most suitable project for adopting the pidof tool.
This commit introduces a redesigned version of pidof
that satisfies the LSB requirements.
In corner cases the behaviour might differ from the former
one as the new version doesn't use any stat(2) calls.
