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).
Related
I have a simple script that checks the process id of some process using ps. When I run it directly on command line, it works fine but does not when I run it in a script. What am I doing wrong?
This works fine:
ps auwx | grep elasticsearch | grep -v grep | grep user | awk '{print $2}' | tail -1
In script, it does not:
#!/bin/bash
#Setting ES Heap to 50GB
ES_HEAP_SIZE="50g"
#Finding dump file to be deleted
FILE_ID=$(ps auwx | grep elasticsearch | grep -v grep | grep user | awk '{print $2}' | tail -1)
FILE_NAME="java_pid$FILE_ID.hprof"
echo "Elasticsearch pid: $FILE_ID"
echo "Dump file name if it exists: $FILE_NAME. Checking now."
if [ -s $FILE_NAME ]
then
rm $FILE_NAME
kill -9 $FILE_ID
#Starting elasticsearch daemon
/data/elasticsearch-1.4.4/bin/elasticsearch -d
else
echo "All good. Dump file $FILE_NAME does not exist."
fi
Personal pet peeve: why do you have six executions in your pipeline when two will handle everything you need?
ps auwx | awk '/elasticsearch/ && /user/ { x=$2 } END{ print x; }'
As an aside, you wanted PID? Because it looks like you're reading PPID.
Hope that helps.
I created this function to kill a process by partial name, put it in bash_profile, and executed it.
when I run it one command at a time manually, everything works.
but when I call the function, it fails with the output: "illegal process id"
function killServer() {
pid=$(ps -fe | grep '[p]rocessName' | awk '{print $2}')
if [[ -n $pid ]]; then
kill $pid
else
echo "Does not exist"
fi
}
output:
kill: illegal process id: i311821
running
ps -fe | grep '[p]rocessName'
gives:
1543721191 1947 1946 0 9:12AM ?? 0:46.76 ../../jdk/bin/java -server -da -XX:PermSize=256m Xrunjdwp:transport=dt_socket,address=8000,suspend=n,server=y -DMonitorDisabled -Xms2048m -Xmx2048m -Dwrapper.port=32000 -com.XXX.YYY.server.util.Main -b 0.0.0.0 -c default
what is the reason for that?
found the problem:
a space after $2 was missing. after the fix, it works:
ps -ef | grep "[X]XX" | grep -v grep | awk '{print $2 }' | xargs kill -9
The script:
#!/bin/bash
SERVICE="$1"
RESULT=`ps -a | sed -n /${SERVICE}/p`
MEM=$(ps aux | sort -rk +4 | grep $1 | grep -v grep | awk '{print $4}' | awk 'NR == 1')
if [ "${RESULT:-null}" = null ]; then
echo "$1 is NOT running"
else
echo "$MEM"
fi
if [ "$MEM" -ge 1 ]; then
mailx -s "Alert: server needs to be checked" me#admins.com
fi
The problem with the ps output piped to sed is even if no process is running it finds itself:
ps aux | sed -n /nfdump/p
root 30724 0.0 0.0 105252 884 pts/1 S+ 14:16 0:00 sed -n /process/p
and them my script bypasses the expected result of "service is not running" and goes straight to echo'ing $MEM, which in this case will be 0.0. Does sed have a grep -v grep eqivalent to get itself out of the way?
Let me add one more example in addition to my comments above. Sed has indeed an equivalent to grep -v: You can negate a match with /RE/! (append a ! to the regex) thus you can try:
ps aux | sed -n '/sed/!{ /nfdump/ p;}'
Here the part inside { ... } is only applied to lines not matching sed.
For the record: there is a command pgrep that can replace your ps sed pipeline, see pgrep in Wikipedia or its manpage.
Try :
ps aux | sed -n '/[n]fdump/p'
or :
ps aux | grep '[n]fdump'
The regex won't be find in the processes list
This follows on from Faulty tail syntax or grep command? but I'm reading a live log entries for given conditions and when they're met continuing the execution of the rest of the script. I'm using this:
tail -Fn0 /var/log/messages | grep -q "CPU utilization" | grep -q "exceeded threshold"
FPC=$(echo $line | awk 'END { print substr($8,1,1) }')
PIC=$(echo $line | awk 'END { print substr($11,1,1) }')
echo FPC $FPC
echo PIC $PIC
echo "Running information gathering"...and rest of script.
Which works perfectly for the conditions detection and further execution, but I don't have the log entry to test for the FPC and PIC variables. I've tried wrapping the tail statement thus:
line=$(tail -Fn0 /var/log/messages | grep -q "CPU utilization" | grep -q "exceeded threshold")
but grep -q exits silently and the $line variable is blank. I've tried:
line=$(tail -Fn0 /var/log/messages | grep -m1 "CPU utilization" | grep -m1 "exceeded threshold")
which doesn't work until I attempt to CONTROL-C out of the script. Then it works fine and continues perfectly. Can someone help please?
I need the variables FPC and PIC later in the script.
Assuming that you don't need these variables later on, you could do something like this:
tail -Fn0 /var/log/messages | \
awk '/CPU utilization/ && /exceeded threshold/ {
print "FPC", substr($8,1,1); print "PIC", substr($11,1,1); exit }'
When the line matches both patterns, print the two parts of it that you are interested in and exit.
If you do need the variables, you could do something like this instead:
line=$(tail -Fn0 /var/log/messages | awk '/CPU utilization/&&/exceeded threshold/{print;exit}')
FPC=$(echo "$line" | awk '{ print substr($8,1,1) }')
PIC=$(echo "$line" | awk '{ print substr($11,1,1) }')
I want to attach to a running process using 'ddd', what I manually do is:
# ps -ax | grep PROCESS_NAME
Then I get a list and the pid, then I type:
# ddd PROCESS_NAME THE_PID
Is there is a way to type just one command directly?
Remark: When I type ps -ax | grep PROCESS_NAME, grep will match both the process and grep command line itself.
There is an easy way to get rid of the grep process:
ps -ax | grep PROCESS_NAME | grep -v ' grep '
(as long as the process you're trying to find doesn't include the string " grep ").
So something like this should work in a script (again, assuming there's only one copy running):
pid=$(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}'\`