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Below I have tried to extract the pid of a running process to check its current ppid
ps -p 1111 -o ppid = $(ps -eo pid,args | awk '/PRD_/ && /startscen\.sh/ && $8 ~ /<string>/' | awk -F" " '{print $1}')
My script is wrong. Is there a better way?
does
ps -ef | awk '/PRD_/ && /startscen\.sh/ {print $3}'
give you what you want? That searchs for a process with "PRD_" and "startscen.sh" in the CMD string, and reports the PPID. If you want to run an additional ps to get info on the parent,
ps -p `ps -ef | awk '/PRD_/ && /startscen\.sh/ {print $3}'`
To check the ppid of a particular process, you use notation like this:
$ ps -p 1111 -o ppid=
This is close to what you've got, but note that the equals sign is immediately after ppid, with no space. This equals sign is not part of an expression, its function with the -o option is to specify custom headers. With this example I've included, you're telling ps to include no header at all, so the output will be just the ppid and nothing else. For example, try ps -p 1 -o ppid=Hello.
If I'm reading this correctly, the rest of your example code appears to be unrelated to your actual question, and is an attempt to collect the pid of perhaps a shell script that is running. So ... as an addendum to this answer, my advice on this point would be to modify the shell script so that it records its own somewhere, so you don't have to rely on parsing the process table to find it. For example, you could add something near the top of startscen.sh that looks like this:
pidfile="/var/run/`basename $0`.pid"
if [ -s "$pidfile" ]; then
if ps "$(cat $pidfile)" >/dev/null; then
echo "ERROR: already running, giving up." >&2
exit 1
fi
fi
trap "rm -f pidfile" 0 1 2 3 5 15
echo $$ > $pidfile
It's not perfect, but this will provide you with some protection against running the script twice at the same time, and will store the pid of the running script in a file where other pids live.
Related
Let's assume I have 3 shell scripts:
script_1.sh
#!/bin/bash
./script_3.sh
script_2.sh
#!/bin/bash
./script_3.sh
the problem is that in script_3.sh I want to know the name of the caller script.
so that I can respond differently to each caller I support
please don't assume I'm asking about $0 cause $0 will echo script_3 every time no matter who is the caller
here is an example input with expected output
./script_1.sh should echo script_1
./script_2.sh should echo script_2
./script_3.sh should echo user_name or root or anything to distinguish between the 3 cases?
Is that possible? and if possible, how can it be done?
this is going to be added to a rm modified script... so when I call rm it do something and when git or any other CLI tool use rm it is not affected by the modification
Based on #user3100381's answer, here's a much simpler command to get the same thing which I believe should be fairly portable:
PARENT_COMMAND=$(ps -o comm= $PPID)
Replace comm= with args= to get the full command line (command + arguments). The = alone is used to suppress the headers.
See: http://pubs.opengroup.org/onlinepubs/009604499/utilities/ps.html
In case you are sourceing instead of calling/executing the script there is no new process forked and thus the solutions with ps won't work reliably.
Use bash built-in caller in that case.
$ cat h.sh
#! /bin/bash
function warn_me() {
echo "$#"
caller
}
$
$ cat g.sh
#!/bin/bash
source h.sh
warn_me "Error: You did not do something"
$
$ . g.sh
Error: You did not do something
g.sh
$
Source
The $PPID variable holds the parent process ID. So you could parse the output from ps to get the command.
#!/bin/bash
PARENT_COMMAND=$(ps $PPID | tail -n 1 | awk "{print \$5}")
Based on #J.L.answer, with more in depth explanations, that works for linux :
cat /proc/$PPID/comm
gives you the name of the command of the parent pid
If you prefer the command with all options, then :
cat /proc/$PPID/cmdline
explanations :
$PPID is defined by the shell, it's the pid of the parent processes
in /proc/, you have some dirs with the pid of each process (linux). Then, if you cat /proc/$PPID/comm, you echo the command name of the PID
Check man proc
Couple of useful files things kept in /proc/$PPID here
/proc/*some_process_id*/exe A symlink to the last executed command under *some_process_id*
/proc/*some_process_id*/cmdline A file containing the last executed command under *some_process_id* and null-byte separated arguments
So a slight simplification.
sed 's/\x0/ /g' "/proc/$PPID/cmdline"
If you have /proc:
$(cat /proc/$PPID/comm)
Declare this:
PARENT_NAME=`ps -ocomm --no-header $PPID`
Thus you'll get a nice variable $PARENT_NAME that holds the parent's name.
You can simply use the command below to avoid calling cut/awk/sed:
ps --no-headers -o command $PPID
If you only want the parent and none of the subsequent processes, you can use:
ps --no-headers -o command $PPID | cut -d' ' -f1
You could pass in a variable to script_3.sh to determine how to respond...
script_1.sh
#!/bin/bash
./script_3.sh script1
script_2.sh
#!/bin/bash
./script_3.sh script2
script_3.sh
#!/bin/bash
if [ $1 == 'script1' ] ; then
echo "we were called from script1!"
elsif [ $1 == 'script2' ] ; then
echo "we were called from script2!"
fi
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I try to convert one command line output into a (or store into a ) variable.
The command is
ps -U root u | grep ruby | wc -l
The output is 1, but when I use
$(ps -U root u | grep ruby | wc -l)
the output is
1: command not found
What happens here?
Here is my snapshot
Here,
$(ps -U root u | grep ruby | wc -l)
You are not saving the output into a variable. So the shell attempts to execute the result (which happens to be 1 in your case). Since it couldn't find a command/function named 1, you get the error.
You probably want:
output=$(ps -U root u | grep ruby | wc -l)
Now, output will have 1 which you can print with:
echo "${output}"
Btw, grep can count itself using the -c option. So wc is unnecessary here:
output=$(ps -U root u | grep -c ruby)
echo "${output}"
In the latter case, the command inside the $(…) is evaluated and the result is then used to create a new command, which the shell then tries to execute. Since there is no command or program named 1, you get the message you are seeing. It easier to see what's happening if you writer echo Result: $(ps -U root u | grep ruby | wc -l). your output would be Result: 1.
To assign to a variable do it like this, using backtics
a=`ps -U root u | grep ruby | wc -l`
I'm trying to have a lightweight memory profiler for the matlab jobs that are run on my machine. There is either one or zero matlab job instance, but its process id changes frequently (since it is actually called by another script).
So here is the bash script that I put together to log memory usage:
#!/bin/bash
pid=`ps aux | grep '[M]ATLAB' | awk '{print $2}'`
if [[ -n $pid ]]
then
\grep VmSize /proc/$pid/status
else
echo "no pid"
fi
when I run this script in bash like this:
./script.sh
it works fine, giving me the following result:
VmSize: 1289004 kB
which is exactly what I want.
Now, I want to run this periodically. So I run it with watch, like this:
watch ./script.sh
But in this case I only receive:
no pid
Please note that I know the matlab job is still running, because I can see it with the same pid on top, and besides, I know each matlab job take several hours to finish.
I'm pretty sure that something is wrong with the quotes I have when setting pid. I just can't figure out how to fix it. Anyone knows what I'm doing wrong?
PS.
In the man page of watch, it says that commands are executed by sh -c. I did run my script like sh -c ./script and it works just fine, but watch doesn't.
Why don't you use a loop with sleep command instead?
For example:
#!/bin/bash
pid=`ps aux | grep '[M]ATLAB' | awk '{print $2}'`
while [ "1" ]
do
if [[ -n $pid ]]
then
\grep VmSize /proc/$pid/status
else
echo "no pid"
fi
sleep 10
done
Here the script sleeps(waits) for 10 seconds. You can set the interval you need changing the sleep command. For example to make the script sleep for an hour use sleep 1h.
To exit the script press Ctrl - C
This
pid=`ps aux | grep '[M]ATLAB' | awk '{print $2}'`
could be changed to:
pid=$(pidof MATLAB)
I have no idea why it's not working in watch but you could use a cron job and make the script log to a file like so:
#!/bin/bash
pid=$(pidof MATLAB) # Just to follow previously given advice :)
if [[ -n $pid ]]
then
echo "$(date): $(\grep VmSize /proc/$pid/status)" >> logfile
else
echo "$(date): no pid" >> logfile
fi
You'd of course have to create logfile with touch.
You might try just running ps command in watch. I have had issues in the past with watch chopping lines and such when they get too long.
It can be fixed by making the terminal you are running the command from wider or changing the column like this (may need to adjust the 160 to your liking):
export COLUMNS=160;
Let's suppose I have a bash script (foo.sh) that in a very simplified form, looks like the following:
echo "hello"
sleep 100 &
ps ax | grep sleep | grep -v grep | awk '{ print $1 } ' | xargs kill -9
echo "bye"
The third line imitates pkill, which I don't have by default on Mac OS X, but you can think of it as the same as pkill. However, when I run this script, I get the following output:
hello
foo: line 4: 54851 Killed sleep 100
bye
How do I suppress the line in the middle so that all I see is hello and bye?
While disown may have the side effect of silencing the message; this is how you start the process in a way that the message is truly silenced without having to give up job control of the process.
{ command & } 2>/dev/null
If you still want the command's own stderr (just silencing the shell's message on stderr) you'll need to send the process' stderr to the real stderr:
{ command 2>&3 & } 3>&2 2>/dev/null
To learn about how redirection works:
From the BashGuide: http://mywiki.wooledge.org/BashGuide/TheBasics/InputAndOutput#Redirection
An illustrated tutorial: http://bash-hackers.org/wiki/doku.php/howto/redirection_tutorial
And some more info: http://bash-hackers.org/wiki/doku.php/syntax/redirection
And by the way; don't use kill -9.
I also feel obligated to comment on your:
ps ax | grep sleep | grep -v grep | awk '{ print $1 } ' | xargs kill -9
This will scortch the eyes of any UNIX/Linux user with a clue. Moreover, every time you parse ps, a fairy dies. Do this:
kill $!
Even tools such as pgrep are essentially broken by design. While they do a better job of matching processes, the fundamental flaws are still there:
Race: By the time you get a PID output and parse it back in and use it for something else, the PID might already have disappeared or even replaced by a completely unrelated process.
Responsibility: In the UNIX process model, it is the responsibility of a parent to manage its child, nobody else should. A parent should keep its child's PID if it wants to be able to signal it and only the parent can reliably do so. UNIX kernels have been designed with the assumption that user programs will adhere to this pattern, not violate it.
How about disown? This mostly works for me on Bash on Linux.
echo "hello"
sleep 100 &
disown
ps ax | grep sleep | grep -v grep | awk '{ print $1 } ' | xargs kill -9
echo "bye"
Edit: Matched the poster's code better.
The message is real. The code killed the grep process as well.
Run ps ax | grep sleep and you should see your grep process on the list.
What I usually do in this case is ps ax | grep sleep | grep -v grep
EDIT: This is an answer to older form of question where author omitted the exclusion of grep for the kill sequence. I hope I still get some rep for answering the first half.
Yet another way to disable job termination messages is to put your command to be backgrounded in a sh -c 'cmd &' construct.
And as already pointed out, there is no need to imitate pkill; you may store the value of $! in another variable instead.
echo "hello"
sleep_pid=`sh -c 'sleep 30 & echo ${!}' | head -1`
#sleep_pid=`sh -c '(exec 1>&-; exec sleep 30) & echo ${!}'`
echo kill $sleep_pid
kill $sleep_pid
echo "bye"
Have you tried to deactivate job control? It's a non-interactive shell, so I would guess it's off by default, but it does not hurt to try... It's regulated by the -m (monitor) shell variable.
This question already has answers here:
Find and kill a process in one line using bash and regex
(30 answers)
Closed 1 year ago.
Sometimes when I try to start Firefox it says "a Firefox process is already running". So I have to do this:
jeremy#jeremy-desktop:~$ ps aux | grep firefox
jeremy 7451 25.0 27.4 170536 65680 ? Sl 22:39 1:18 /usr/lib/firefox-3.0.1/firefox
jeremy 7578 0.0 0.3 3004 768 pts/0 S+ 22:44 0:00 grep firefox
jeremy#jeremy-desktop:~$ kill 7451
What I'd like is a command that would do all that for me. It would take an input string and grep for it (or whatever) in the list of processes, and would kill all the processes in the output:
jeremy#jeremy-desktop:~$ killbyname firefox
I tried doing it in PHP but exec('ps aux') seems to only show processes that have been executed with exec() in the PHP script itself (so the only process it shows is itself.)
pkill firefox
More information: http://linux.about.com/library/cmd/blcmdl1_pkill.htm
Also possible to use:
pkill -f "Process name"
For me, it worked up perfectly. It was what I have been looking for.
pkill doesn't work with name without the flag.
When -f is set, the full command line is used for pattern matching.
You can kill processes by name with killall <name>
killall sends a signal to all
processes running any of the specified
commands. If no signal name is
specified, SIGTERM is sent.
Signals can be specified either by
name (e.g. -HUP or -SIGHUP ) or by number (e.g.
-1) or by option -s.
If the command name is not regular
expression (option -r) and contains a
slash (/), processes executing that
particular file will be selected for
killing, independent of their name.
But if you don't see the process with ps aux, you probably won't have the right to kill it ...
A bit longer alternative:
kill `pidof firefox`
The easiest way to do is first check you are getting right process IDs with:
pgrep -f [part_of_a_command]
If the result is as expected. Go with:
pkill -f [part_of_a_command]
If processes get stuck and are unable to accomplish the request you can use kill.
kill -9 $(pgrep -f [part_of_a_command])
If you want to be on the safe side and only terminate processes that you initially started add -u along with your username
pkill -f [part_of_a_command] -u [username]
Kill all processes having snippet in startup path. You can kill all apps started from some directory by for putting /directory/ as a snippet. This is quite usefull when you start several components for the same application from the same app directory.
ps ax | grep <snippet> | grep -v grep | awk '{print $1}' | xargs kill
* I would prefer pgrep if available
Strange, but I haven't seen the solution like this:
kill -9 `pidof firefox`
it can also kill multiple processes (multiple pids) like:
kill -9 `pgrep firefox`
I prefer pidof since it has single line output:
> pgrep firefox
6316
6565
> pidof firefox
6565 6316
Using killall command:
killall processname
Use -9 or -KILL to forcefully kill the program (the options are similar to the kill command).
On Mac I could not find the pgrep and pkill neither was killall working so wrote a simple one liner script:-
export pid=`ps | grep process_name | awk 'NR==1{print $1}' | cut -d' ' -f1`;kill $pid
If there's an easier way of doing this then please share.
To kill with grep:
kill -9 `pgrep myprocess`
more correct would be:
export pid=`ps aux | grep process_name | awk 'NR==1{print $2}' | cut -d' ' -f1`;kill -9 $pid
I normally use the killall command.
Check this link for details of this command.
I was asking myself the same question but the problem with the current answers is that they don't safe check the processes to be killed so... it could lead to terrible mistakes :)... especially if several processes matches the pattern.
As a disclaimer, I'm not a sh pro and there is certainly room for improvement.
So I wrote a little sh script :
#!/bin/sh
killables=$(ps aux | grep $1 | grep -v mykill | grep -v grep)
if [ ! "${killables}" = "" ]
then
echo "You are going to kill some process:"
echo "${killables}"
else
echo "No process with the pattern $1 found."
return
fi
echo -n "Is it ok?(Y/N)"
read input
if [ "$input" = "Y" ]
then
for pid in $(echo "${killables}" | awk '{print $2}')
do
echo killing $pid "..."
kill $pid
echo $pid killed
done
fi
kill -9 $(ps aux | grep -e myprocessname| awk '{ print $2 }')
If you run GNOME, you can use the system monitor (System->Administration->System Monitor) to kill processes as you would under Windows. KDE will have something similar.
The default kill command accepts command names as an alternative to PID. See kill (1). An often occurring trouble is that bash provides its own kill which accepts job numbers, like kill %1, but not command names. This hinders the default command. If the former functionality is more useful to you than the latter, you can disable the bash version by calling
enable -n kill
For more info see kill and enable entries in bash (1).
ps aux | grep processname | cut -d' ' -f7 | xargs kill -9 $
awk oneliner, which parses the header of ps output, so you don't need to care about column numbers (but column names). Support regex. For example, to kill all processes, which executable name (without path) contains word "firefox" try
ps -fe | awk 'NR==1{for (i=1; i<=NF; i++) {if ($i=="COMMAND") Ncmd=i; else if ($i=="PID") Npid=i} if (!Ncmd || !Npid) {print "wrong or no header" > "/dev/stderr"; exit} }$Ncmd~"/"name"$"{print "killing "$Ncmd" with PID " $Npid; system("kill "$Npid)}' name=.*firefox.*