Commit ac19cb62 authored by Masatake YAMATO's avatar Masatake YAMATO

pidof: allow to change a separator put between pids

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
    $ ./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: 's avatarMasatake YAMATO <>
parent 3497521d
Pipeline #17985786 passed with stage
in 1 minute and 29 seconds
......@@ -27,6 +27,8 @@ pidof -- find the process ID of a running program.
.IR omitpid[,omitpid..] ]
.RB [ \-o
.IR omitpid[,omitpid..].. ]
.RB [ \-S
.IR separator ]
.B program
.RB [ program.. ]
......@@ -47,6 +49,9 @@ shells running the named scripts.
Tells \fIpidof\fP to omit processes with that process id. The special
pid \fB%PPID\fP can be used to name the parent process of the \fIpidof\fP
program, in other words the calling shell or shell script.
.IP "-S \fIseparator\fP"
Use \fIseparator\fP as a separator put between pids. Used only when
more than one pids are printed for the program.
.B 0
......@@ -64,6 +64,7 @@ static int __attribute__ ((__noreturn__)) usage(int opt)
fputs(_(" -c, --check-root omit processes with different root\n"), fp);
fputs(_(" -x also find shells running the named scripts\n"), fp);
fputs(_(" -o, --omit-pid <PID,...> omit processes with PID\n"), fp);
fputs(_(" -S, --separator SEP use SEP as separator put between PIDs"), fp);
fputs(USAGE_HELP, fp);
fputs(USAGE_VERSION, fp);
......@@ -287,12 +288,14 @@ int main (int argc, char **argv)
int found = 0;
int first_pid = 1;
const char *opts = "scnxmo:?Vh";
const char *separator = " ";
const char *opts = "scnxmo:S:?Vh";
static const struct option longopts[] = {
{"check-root", no_argument, NULL, 'c'},
{"single-shot", no_argument, NULL, 's'},
{"omit-pid", required_argument, NULL, 'o'},
{"separator", required_argument, NULL, 's'},
{"help", no_argument, NULL, 'h'},
{"version", no_argument, NULL, 'V'},
{NULL, 0, NULL, 0}
......@@ -324,6 +327,9 @@ int main (int argc, char **argv)
pidof_root = pid_link(getpid(), "root");
case 'S':
separator = optarg;
case 'V':
......@@ -357,7 +363,7 @@ int main (int argc, char **argv)
first_pid = 0;
printf ("%ld", (long) procs[i].pid);
} else {
printf (" %ld", (long) procs[i].pid);
printf ("%s%ld", separator, (long) procs[i].pid);
if (opt_single_shot) break;
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