shell command to find a process id and attach to it? - bash

I want to attach to a running process using 'ddd', what I manually do is:
# ps -ax | grep PROCESS_NAME
Then I get a list and the pid, then I type:
# ddd PROCESS_NAME THE_PID
Is there is a way to type just one command directly?
Remark: When I type ps -ax | grep PROCESS_NAME, grep will match both the process and grep command line itself.

There is an easy way to get rid of the grep process:
ps -ax | grep PROCESS_NAME | grep -v ' grep '
(as long as the process you're trying to find doesn't include the string " grep ").
So something like this should work in a script (again, assuming there's only one copy running):
pid=$(ps -ax | grep $1 | grep -v ' grep ' | awk '{print $1}')
ddd $1 ${pid}
If you call your script dddproc, you can call it with:
dddproc myprogramname
Although I'd add some sanity checks such as detecting if there's zero or more than one process returned from ps and ensuring the user supplies an argument.

As separate commands:
% PID=`ps -ax | grep ${PROCESS_NAME} | grep -v grep | cut -d ' ' -f 1-2`
% ddd ${PROCESS_NAME} ${PID}
In one line:
% PID=`ps -ax | grep ${PROCESS_NAME} | grep -v grep | cut -d ' ' -f 1-2` && ddd ${PROCESS_NAME} ${PID}

ddd <process_name> `pgrep <process_name>`

you can use pggrep to find the process

You can use awk to both filter and get the column you want. The "exit" limits the ps results to the first hit.
function ddd_grep() {
ddd $(ps -ax | awk -v p="$1" '$4 == p { print $1; exit 0; }');
}
ddd_grep PROCESS_NAME
You may have to adjust the columns for your ps output. Also you can change the == to ~ for regex matching.

Do this way -
ddd PROCESS_NAME \`ps -ax | grep PROCESS_NAME | grep -v grep | awk '{print $1}'\`

Related

how to retrieve open file handle count for a pid via shell script

I am trying to retreive open file handle count for a particular PID in a variable via shell script and displaying the same.It is not showing the correct count. Can someone please advise?
pid=$(ps -ef | grep 'instance="AC"' | grep -v grep | awk '{print $2}') f_count=$(ls /proc/$'{pid}' | wc -l)
Expected output:
=============
When executed in command line , it shows
ps -ef | grep 'service_instance="AC"' | grep -v grep | awk '{print $2}'
25939
ls /proc/25939/fd | wc -l
98
Actual Output:
f_count= 0
Appreciate your help, thanks
Suggesting to replace:
pid=$(ps -ef | grep 'instance="AC"' | grep -v grep | awk '{print $2}')
With:
pid=$(pgrep -f 'instance="AC"')
Notice that pid takes the first matched process.
If there are more than one matched process pgrep returns multiple lines.
Suggesting to replace:
f_count=$(ls /proc/$'{pid}' | wc -l)
with
f_count=$(ls /proc/${pid}/fd | wc -l)
Or all together in one line
f_count=$(ls /proc/$(pgrep -f 'instance="AC"')/fd | wc -l)

One-liner to retrieve path from netstat port

I'm looking to create a one liner that, given a port number (2550) uses the returned value from netstat would allow me to then run the resulting output against ps -ef to return the path of the process in question. I have:
ps -ef | grep $(netstat -tonp | grep 2550 | awk '{split($7,a,"/"); print a[1]}')
and whilst I know
netstat -tonp | grep 2550 | awk '{split($7,a,"/"); print a[1]}'
returns the expected resulted, the subsequent grep tells me that there is no such file or directory (but, if I do the ps -ef | grep **) it works just fine... I'm obviously missing something... well, obvious, but I can't see what?
try something like (it takes the first PID/port corresponding, not all):
Port=2550;ps -f --pid $( netstat -tonp | awk -F '[ \t/]+' -v Port=$Port '$0 ~ "([0-9]+[.:]){4}" Port { PID= $7;exit}; END { print PID+0 }' ) | sed 's/^\([^ \t]*[ \t]*\)\{7\}//'
the last sed is assuming a ps reply like this (space are important):
usertest 4408 4397 0 09:43 pts/6 00:00:00 ssh -p 22 -X -l usertest 198.198.131.136
for every PID and with no ending sed:
Port=2550; ps -ef | awk -v PIDs="$( netstat -tonp | awk -F '[ \t/]+' -v Port=${Port} '$0 ~ (":" Port) { print $7}' )" 'BEGIN{ split( PIDs, aTemp, /\n/); for( PID in aTemp) aPID[ aTemp[PID] ] }; $2 in aPID { sub( /^([^ \t]*[ \t]*){7}/, ""); print}'
This will give you the pids:
<sudo> netstat -tulpen | awk '$4 ~ /:2550$/{sub("/.*","",$NF);print $NF}'
You can use xargs to pass the pid to ps:
netstat -tulpen | awk '$4 ~ /:2550$/{sub("/.*","",$NF);print $NF}' | xargs -P 1 ps -o pid,cmd -p

How to reference multiple string values in array in Shell script

I am trying to store multiple string in for loop but it giving me unwanted answer.
My code is :
#!/bin/bash
declare -a arr=("ps -ef | grep icsmpgum | grep $USER | grep -v grep | awk '{print $9,$8}' | awk '{print $1}'")
for i in "${arr[#]}"
do
echo "$i"
done
The output of
ps -ef | grep icsmpgum | grep $USER | grep -v grep | awk '{print $9,$8}' | awk '{print $1}'
is :
icsmpgum
ABC
DEF
I want to refer to these 3 string values in for loop but after applying for loop as mention above it giving me output as :
Output :
ps -ef | grep icsmpgum | grep tsaprm1 | grep -v grep | awk '{print ,}' | awk '{print }'
How should I store these string values in variables ?
You need to use a command substitution, rather than quoting the command:
arr=( $(ps -ef | grep icsmpgum | grep $USER | grep -v grep | awk '{print $9,$8}' | awk '{print $1}') )
I suspect that this will work but there's a lot of further tidying up to be done; all the filtering that you want to do is possible in one call to awk:
arr=( $(ps -ef | awk -v user="$USER" '!/awk/ && /icsmpgum/ && $0 ~ user { print $9 }') )
As mentioned in the comments, there are potential risks to building an array like this (e.g. glob characters such as * would be expanded and you would end up with extra values in the array). A safer option would be to use a process substitution:
read -ra arr < <(ps -ef | awk -v user="$USER" '!/awk/ && /icsmpgum/ && $0 ~ user { print $9 }')

How to feed the output of one pipe to another pipe?

I have a command here:
ps aux | grep -i java | grep -i test | awk '{ print $2 }'
which gives only one process id like 1201. Now I want to kill them by piping the 1201 to kill command.
How do I do that?
I tried tee like this:
ps aux | grep -i java | grep -i test | awk '{ print $2 }' | tee >(kill -9)
but that gives:
kill: usage: kill [-s sigspec | -n signum | -sigspec] pid | jobspec ... or kill -l [sigspec]
where I'm making mistake?
Use xargs to convert standard input to command-line parameters
ps aux | grep -i java | grep -i test | awk '{ print $2 }' | xargs kill

Shell Script to find PID of ssh and kill the PID if present

I am trying to write a script to find a reverse SSH PID and kill it if present. I am stuck on "awk" as it gives error. below is the script:
a=('ps -aef | grep "ssh -fN" | grep -v grep | awk '{ print $2 }'')
if [ -n "$a" ]
then
echo "String \"$a\" is not null."
kill -9 "$a"
fi
I commented out if, then, kill and fi lines to debug the script. I get following error:
String "ps -aef | grep "ssh -fN" | grep -v grep | awk {" is not null.
I believe parenthesis for awk is creating the problem and I am unable to get a workaround for this. On Command line, this works perfectly and returns the correct PID.
ps -aef | grep "ssh -fN" | grep -v grep | (awk '{ print $2 }'
Once the PID is passed on to variable "a", I need to issue kill command. OS is Centos 6.4
P.S: I am not fluent on scripting but trying to achieve an objective. Help will be highly appreciated!
There are multiple problems with your script.
You need command substitution to store the output of ps pipeline into an array.
You need to check for the number of elements in the array.
Refer to the array instead of the variable.
The following might work for you:
pids=( $(ps -ef | grep '[s]sh -fN' | awk '{print $2}') )
if [ "${#pids[#]}" -gt 0 ]; then
kill -9 "${pids[#]}";
fi
First, if you have grep and then awk, you can get rid of the greps:
ps -aef | grep "ssh -fN" | grep -v grep | awk '{ print $2 }'
ps -aef |awk ' { if ( ($0 ~ /ssh -FN/) && (! $0 ~ /grep/) ) { print $2 } }'
However, instead of using ps, use pgrep.
pgrep -f "ssh -[fN][fN]" # Will match against either 'ssh -fN' or 'ssh -Nf'
There is even a pkill that will do the entire command for you:
pkill -f "ssh -[fN][fN]"
That will find all of the processes that match that particular string and kill them (if they exist).

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