I have written a very short script that gets pid of $1 then kills the process. I have a few questions / requests for improvement. (OSX)
#!/bin/bash
getpid=$(ps aux -O start | grep -i "$1" | grep -v grep | grep -v $0 | awk '{ if (NR==1) {print $2}}')
kill $getpid
For example:
$ ~/killpro.sh java
Which kills the most recent instance of java.
Or:
$ ~/killpro.sh chrome
To kill Google Chrome, obviously.
First, is there any practical way to get this strung together into a single line, using read -p perhaps, so that it can in turn be aliased and become something like:
$ killpro
$ Enter name: chrome
$
Not that it's significantly easier, in fact it's slightly more work, but it bypasses the need to type a path and shell extension which is desirable.
Second, is there anything fundamentally wrong with my initial approach / am I missing something obvious that negates the need for any this?
Any feedback is appreciated.
Thanks in advance, I'm (as you can tell) new to this.
My advice is to use pkill instead. From the manual page:
NAME
pgrep, pkill -- find or signal processes by name
Most scripts with grep | awk are a useless use of grep and should be refactored to use just Awk.
#!/bin/bash
# Maybe add a case for $# > 1 and quit with an error message
# Or maybe loop over arguments if there is more than one
case $# in 0) read -p "Process name? " proc;; *) proc=$1;; esac
# Maybe your ps aux doesn't have the command in $11 -- adapt
kill $(ps aux -O start |
awk -v name="$proc" 'NR>1 && tolower($11) ~ tolower(name) {print $2}')
Your comments indicate you seek to kill the "latest" process (by which metric?) but your code, and this code, attempts to kill all the instances. If you want the most recently started process, the PID is not a good indicator; you should look at process start times etc. The output of ps is heavily system-dependent so you should probably post a separate question with more details about your OS if you need help figuring that out.
This particular problem regularly gets beaten to death several times a month here, so you should probably look at other implementations for inspiration. My recommendation would be "don't do that" but since you already did, I suppose it makes sense to point out the flaws and attempt to solidify the code. But if you don't have a compelling reason why you cannot install pkill, you should probably just use that (and if you do, using a properly debugged and tested script is way better than writing your own from scratch).
You could just use awk alone with getline to call out to ps and get the data you want:
awk -vv_kp="bash" 'BEGIN{ cmd="ps -axu -O T | grep "v_kp" |head -1"; cmd | getline var; close(cmd); split(var,var2," ");print var2[2];}'
or less awk, more shell:
awk -vv_kp="bash" 'BEGIN{ cmd="ps -axu -O T | grep "v_kp" |head -1|cut -d\" \" -f2"; cmd | getline var; close(cmd); print var;}'
Related
I have read that egrep is deprecated in favour of grep -E so I'm looking back at my code and changing it where I find it.
But I see that the results are not always as expected.
With egrep, I get my list of running Oracle instances:
ps -ef|grep [p]mon|awk -F'ora_pmon_' '{print $NF}'|egrep -v 'ASM|^$'
halana
bila
halsasa
loana
However with grep -E, I get part of the awk in the results:
ps -ef|grep [p]mon|awk -F'ora_pmon_' '{print $NF}'|grep -Ev 'ASM|^$'
halana
bila
halsasa
{print $NF}
loana
Excluding 'print' obviously works but is it the right way to go about it?:
ps -ef|grep [p]mon|awk -F'ora_pmon_' '{print $NF}'|grep -Ev 'ASM\|^$|print'
halana
bila
halsasa
loana
Is this effect due to the fact that grep -E allows additional regular expression syntax?
Suggesting to simplify your line, eliminate all grep commands:
pgrep -af 'pmon'|awk -F'ora_pmon_' '!/ASM|^$/{print $NF}'
Fold first grep command into pgrep command.
Fold second grep command into awk scirpt !/ASM|^$/{print $NF}
About grep -E vs egrep
There is no difference whatsoever between these commands (they're even provided by the same executable on most operating systems); your old code was vulnerable to this bug too, and if you didn't see it, that's just a matter of being "lucky" in ps getting enough of the process list read before the shell gets to setting up the awk part of the pipeline.
Solving Your Problem
The right answer is already given by #DudiBoy, but the answer with the smallest possible change would be to make your awk (assuming it has GNU extensions and accepts regexes in the field separator specification) escape the string pmon the same way your first grep command does:
ps -ef|grep '[p]mon'|awk -F'ora_[p]mon_' '{print $NF}'|grep -Ev 'ASM|^$'
I am trying to execute a couple of complicated grep commands via a shells script that work fin in the terminal manually executed. I can't for the life of me figure out why this doesn't work.
The goal of the first grep is to get out any process id attached to the parent myPattern. The 2nd get the process id of the process myPattern
Currently my shell script
returns nothing for the 1st.
ignores the "grep -v 'grep'" part in the 2nd.
#!/bin/sh
ps -ef | grep "$(ps -ef | grep 'myPattern' | grep -v grep | awk '{print $2}')" | grep -v grep | grep -v myPattern | awk '{print $2}'
ps -ef | grep 'myPattern' | grep -v 'grep' | awk '{print $2}'
This works fine when run in the terminal manually. Any ideas where i have stuffed this up?
Your first command is vague. I don't think it would reliably do what you describe. It also does not guard against getting the id of the first grep call. The second one works for me. For the fists query it highly depends on the system you are using. It's easier to use pstree to show you the whole process tree under a pid. Like:
pstree -p 1782 | sed 's/-/\n/g' | sed -n -e 's/.*(\([0-9]\+\)).*/\1/p'
You need to limit pid to be a single value. If you have more values, then you have to loop through them. If you don't have pstree, then you can craft some loop around ps. Make note that even if you current commands worked, then thwy would catch only one level parent/child relationships. pstree does any level.
I also have to tell you that a process can escape original parent as a parent process by forking.
In any case without exact details what you are trying to achieve and why, and on what platform it is hard to give you a great answer. Also these utilities albeit present virtually everywhere are not as portable as one would wish.
One more note - /bin/sh is often not your current shell. On many linux systems user has a default shell of bash and /bin/sh is dash or some other shell variant. So if you see diffs with what you have in console and script, it can be difference in actual shell you are using.
Based on user feedback it would be much easier to have something like this in the java process launching script:
java <your params here> &
echo $! > /var/run/myprog.pid
Then the kill script would look like echo /var/run/myprog.pid | xargs kill. There are shorter commands but I think this is more portable. Give actual code if you want more specific.
I have tried all kinds of filters using grep to try and solve this but just cannot crack it.
cpumem="$(ps aux | grep -v 'grep' | grep 'firefox-bin' | awk '{printf $3 "\t" $4}'
I am extracting the CPU and Memory usage for a process and when I run it from the command line, I get the 2 fields outputted correctly:
ps aux | grep -v 'grep' | grep 'firefox-bin' | awk '{printf $3 "\t" $4}'
> 1.1 4.4
but the same command executed from within the bash script produces this:
cpumem="$(ps aux | grep -v 'grep' | grep 'firefox-bin' | awk '{printf $3 "\t" $4}')"
echo -e cpumem
> 1.1 4.40.0 0.10.0 0.0
I am guessing that it is picking up 3 records, but I just don't know where from.
I am filtering out any other grep processes by using grep -v 'grep', can someone offer any suggestions or a more reliable way ??
Maybe you have 3 records because 3 firefox are running (or one is running, and it is threading itself).
You can avoid the grep hazzle by giving ps and option to select the processes. E.g. the -C to select processes by name. With ps -C firefox-bin you get only the firefox processes. But this does not help at all, when there is more than one process.
(You can also use the ps option to output only the columns you want, so your line would be like
ps -C less --no-headers -o %cpu,%mem
).
For the triple-record you must come up with a solution, what should happen, where more than one is running. In a multiuser environment with programms that are threading there can always be situations where you have more than one process of a kind. There are many possible solution where none can help you, as you dont say, way you are going to do with it. One can think of solutions like selecting only from one user, and only the one with the lowest pid, or the process-leader in case of groups, to change the enclosing bash-script to use a loop to handle the multiple values or make it working somehow different when ps returns multiple results.
I was not able to reproduce the problem, but to help you debug, try print $11 in your awk command, that will tell you what process it is talking about
cpumem="$(ps aux | grep -v 'grep' | grep 'firefox-bin' | awk '{printf $3 "\t" $4 "\t" $11 "\n"}')"
echo -e cpumem
It's actually an easy fix for the output display; In your echo statement, wrap the variable in double-quotes:
echo -e "$cpumem"
Without using double-quotes, newlines are not preserved by converting them to single-spaces (or empty values). With quotes, the original text of the variable is preserved when outputted.
If your output contains multiple processes (i.e. - multiple lines), that means your grep actually matched multiple lines. There's a chance a child-process is running for firefox-bin, maybe a plugin/container? With ps aux, the 11th column will tell you what the actual process is, so you can update your awk to be the following (for debugging):
awk '{printf $3 "\t" $4 "\t" $11}'
I am writing a script to monitor the CPU and MEM of any given process. For that i need to send in the name of the process to be monitored as a commandline argument. For example.
./monitorscript <pname>
I need to get the pid of the process in the script so that i can use a ps -p <pid> inside.
How do i get the pid of a process given its process name?
I understand that there might be multiple processes in the same name. I just want to get the first process out of that list.
The answer above was mostly correct, just needed some tweaking for the different parameters in Mac OSX.
ps -A | grep [f]irefox | awk '{print $1}'
You can use the pgrep command like in the following example
$ pgrep Keychain\ Access
44186
You can install pidof with Homebrew:
brew install pidof
pidof <process_name>
This solution matches the process name more strictly:
ps -Ac -o pid,comm | awk '/^ *[0-9]+ Dropbox$/ {print $1}'
This solution has the following advantages:
it ignores command line arguments like tail -f ~/Dropbox
it ignores processes inside a directory like ~/Dropbox/foo.sh
it ignores processes with names like ~/DropboxUID.sh
This is the shortest command I could find that does the job:
ps -ax | awk '/[t]he_app_name/{print $1}'
Putting brackets around the first letter stops awk from finding the awk process itself.
Try this one:
echo "$(ps -ceo pid=,comm= | awk '/firefox/ { print $1; exit }')"
The ps command produces output like this, with the PID in the first column and the executable name (only) in the second column:
bookworm% ps -ceo pid=,comm=
1 launchd
10 kextd
11 UserEventAgent
12 mDNSResponder
13 opendirectoryd
14 notifyd
15 configd
...which awk processes, printing the first column (pid) and exiting after the first match.
You can try this
pid=$(ps -o pid=,comm= | grep -m1 $procname | cut -d' ' -f1)
ps -o ppid=$(ps -ax | grep nameOfProcess | awk '{print $1}')
Prints out the changing process pid and then the parent PID. You can then kill the parent, or you can use that parentPID in the following command to get the name of the parent process:
ps -p parentPID -o comm=
For me the parent was 'login' :\
Why don't you run TOP and use the options to sort by other metrics, other than PID? Like, highest used PID from the CPU/MEM?
top -o cpu <---sorts all processes by CPU Usage
I'm trying to create a shell script getting the process id of the Skype app on my Mac.
ps -clx | grep 'Skype' | awk '{print $2}' | head -1
The above is working fine, but there are two problems:
1)
The grep command would get all process if their name just contains "Skype". How can I ensure that it only get the result, if the process name is exactly Skype?
2)
I would like to make a shell script from this, which can be used from the terminal but the process name should be an argument of this script:
#!/bin/sh
ps -clx | grep '$1' | awk '{print $2}' | head -1
This isn't returning anything. I think this is because the $2 in the awk is treated as an argument too. How can I solve this?
Your ps -cl1 output looks like this:
UID PID PPID F CPU PRI NI SZ RSS WCHAN S ADDR TTY TIME CMD
501 185 172 104 0 31 0 2453272 1728 - S ffffff80145c5ec0 ?? 0:00.00 httpd
501 303 1 80004004 0 31 0 2456440 1656 - Ss ffffff8015131300 ?? 0:11.78 launchd
501 307 303 4004 0 33 0 2453456 7640 - S ffffff8015130a80 ?? 0:46.17 distnoted
501 323 303 40004004 0 33 0 2480640 9156 - S ffffff80145c4dc0 ?? 0:03.29 UserEventAgent
Thus, the last entry in each line is your command. That means you can use the full power of regular expressions to help you.
The $ in a regular expression means the end of the string, thus, you could use $ to specify that not only does the output must have Skype in it, it must end with Skype. This means if you have a command called Skype Controller, you won't pull it up:
ps -clx | grep 'Skype$' | awk '{print $2}' | head -1
You can also simplify things by using the ps -o format to just pull up the columns you want:
ps -eo pid,comm | grep 'Skype$' | awk '{print $1}' | head -1
And, you can eliminate head by simply using awk's ability to select your line for you. In awk, NR is your record number. Thus you could do this:
ps -eo pid,comm | grep 'Skype$' | awk 'NR == 1 {print $1}'
Heck, now that I think of it, we could eliminate the grep too:
ps -eo pid,comm | awk '/Skype$/ {print $1; exit}'
This is using awk's ability to use regular expressions. If the line contains the regular expression, 'Skype$', it will print the first column, then exit
The only problem is that if you had a command Foo Skype, this will also pick it up. To eliminate that, you'll have to do a bit more fancy footwork:
ps -eo pid,comm | while read pid command
do
if [[ "$command" = "Skype" ]]
then
echo $pid
break
fi
done
The while read is reading two variables. The trick is that read uses white space to divide the variables it reads in. However, since there are only two variables, the last one will contain the rest of the entire line. Thus if the command is Skype Controller, the entire command will be put into $command even though there's a space in it.
Now, we don't have to use a regular expression. We can compare the command with an equality.
This is longer to type in, but you're actually using fewer commands and less piping. Remember awk is looping through each line. All you're doing here is making it more explicit. In the end, this is actually much more efficient that what you originally had.
If pgrep is available on Mac, you can use pgrep '^Skype$'. This will list the process id of all processes called Skype.
You used the wrong quotes in your script:
ps -clx | grep "$1" | awk '{print $2}' | head -1
or
pgrep "^$1$"
The problem with your second example is that the $1 is in single quotes, which prevents bash from expanding the variable. There is already a utility that accomplishes what you want without manually parsing ps output.
pgrep "$1"
You can do this in AppleScript:
tell application "System Events"
set skypeProcess to the process "Skype"
set pid to the unix id of skypeProcess
pid
end tell
which means you can use 'osascript' to get the PID from within a shell script:
$ osascript -e "tell application \"System Events\"" -e "set skypeProcess to the process \"Skype\"" -e "set pid to the unix id of skypeProcess" -e "pid" -e "end tell"
3873
You can format the output of ps using the -o [field],... and list by process name using -C [command_name] ;however, ps will still print the column header, which can be removed by piping it through grep -v PID
ps -o pid -C "$1" |grep -v PID
where $1 would be the command name (in this case Skype)
I'd so something like:
ps aux | grep Skype | awk 'NR==1 {print $2}'
==== UPDATE ====
Use the parameter without quotes and use single quotes for awk
#!/bin/bash
ps aux | grep $1 | awk 'NR==1 {print $2}'
Method 1 - Use awk
I don't see any reason to use the -l flag (long format), I also don't see any reason to use grep and awk at the same time: awk has grep capability built in. Here is my plan: use ps and output just 2 columns: pid and command, then use awk to pick out what you want:
ps -cx -o pid,command | awk '$2 == "Skype" { print $1 }'
Method 2 - Use bash
This method has the advantage that if you already script in bash, you don't even need awk, which save one process. The solution is longer than the other method, but very straight forward.
#!/bin/bash
ps -cx -o pid,command | {
while read pid command
do
if [ "_$command" = "_$1" ]
then
# Do something with the pid
echo Found: pid=$pid, command=$command
break
fi
done
}
pgrep myAwesomeAppName
This works great under Catalina 10.15.2
Use double quotes to allow bash to perform variable substitution.
Single quotes disable bash variable substitution mechanism.
ps -clx | grep "$1" | awk "{print $2}" | head -1