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
See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
Support standard and high intensity colors. The default
ncurses colors ARE the high intensity colors - represented
via an 8 bit ansi escape sequence here.
See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
Support standard and high intensity colors. The default
ncurses colors ARE the high intensity colors - represented
via an 8 bit ansi escape sequence here.
We read /proc/stat using a statically sized buffer. This was increased
to 64kB in 2005 via commit 777fcd3cf1 "/proc/stat for 1024 CPUs".
Unfortunately in 2020, 1024 CPUs is not enough for anyone. I have a
large machine where /proc/stat is 74kB, and vmstat gives incorrect
output.
Double the buffer to 128kB in the confidence that 2048 CPUs is actually
enough for anyone.
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
New command, pwait! Waits for another process to finish just like
pgrep finds or pkill kills another process.
References:
procps-ng/procps!97
Signed-off-by: Craig Small <csmall@dropbear.xyz>
With glibc, each time the strftime() function is used (twice per process
in a typical ps -fe run), a stat("/etc/localtime") system call is used
to determine the timezone. Not only does this add extra system call
overhead, but when multiple ps processes are trying to access this
file (or multiple glibc programs using strftime) in parallel, this can
trigger significant lock contention within the OS kernel.
Since ps is not intended to run for long periods of time as a
daemon (during which the system timezone could be altered and PS might
reasonably be expected to adapt its output), there is no benefit to
repeatedly doing this stat(). To stop this behavior, explicitly set the
TZ variable to its default value (:/etc/localtime) whenever it is unset.
glibc will then cache the stat() result.
With glibc, each time the strftime() function is used (twice per process
in a typical ps -fe run), a stat("/etc/localtime") system call is used
to determine the timezone. Not only does this add extra system call
overhead, but when multiple ps processes are trying to access this
file (or multiple glibc programs using strftime) in parallel, this can
trigger significant lock contention within the OS kernel.
Since ps is not intended to run for long periods of time as a
daemon (during which the system timezone could be altered and PS might
reasonably be expected to adapt its output), there is no benefit to
repeatedly doing this stat(). To stop this behavior, explicitly set the
TZ variable to its default value (:/etc/localtime) whenever it is unset.
glibc will then cache the stat() result.
While sysctl did change the order of /run and /etc to match
systemd in the referenced commit, the Debian bug report that
brought it to light was not documented.
References:
commit 24a1574f0ahttps://bugs.debian.org/950788
While sysctl did change the order of /run and /etc to match
systemd in the referenced commit, the Debian bug report that
brought it to light was not documented.
References:
commit 24a1574f0ahttps://bugs.debian.org/950788
If a hash results report was output (via ATEOJ_RPTHSH)
a portion is devoted to occupied table entries ordered
by depth. There is a possibility that some depths will
not be found among existing occupied table entries and
to avoid any confusion probably should not be printed.
[ to illustrate the potential for confusion prior to ]
[ this patch, force a very small table size (like 8) ]
[ and then arrange to trigger the end-of-job report. ]
So this patch ensures only 'in use' entries are shown.
[ admittedly, all of the remaining logic in the loop ]
[ could/should be subordinate to this new 'if' test, ]
[ but we will keep the change to a minimum. besides, ]
[ there's no harm subtracting/adding a zero numdepth ]
[ especially since the chance of a zero is very low. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
So as to not obscure the results from this new target,
we'll redirect that final 'make clean' output to null.
Signed-off-by: Jim Warner <james.warner@comcast.net>
