Shell: Terminating Long-Running Processes

Table of Contents

I’m sure everyone has had the experience of a server process that was created by some developer and continues to run indefinitely without ending. This script comes in handy in such situations. When you schedule it to run regularly with tools like crontab, it will terminate these seemingly never-ending processes for you. It’s similar to scripts like Terminating Excessive Apache (httpd) Child Processes and Listing Process Execution Directories.

Code

I ran this on an AWS EC2 Amazon Linux server.

#!/bin/bash
for pid in `ps aux | grep crawler | grep -v grep | tr -s ' ' | cut -d ' ' -f2`
do
line=`ps --pid ${pid} -eo pid,etimes | grep ${pid}`
duration=`cut -d' ' -f 2 <<< ${line}`
if [ -z $duration ]
then
continue
fi
if [ $duration -ge 345600 ]
then
echo $duration
sudo kill $pid
fi
done

#!/bin/bash

for pid in `ps aux | grep crawler | grep -v grep | tr -s ' ' | cut -d ' ' -f2`

line=`ps --pid ${pid} -eo pid,etimes | grep ${pid}`

duration=`cut -d' ' -f 2 <<< ${line}`

if [ -z $duration ]

then

continue

if [ $duration -ge 345600 ]

then

echo $duration

sudo kill $pid

done

Explanation

for Loop

for pid in `ps aux | grep target_name | grep -v grep | tr -s ' ' | cut -d ' ' -f2`

1	for pid in `ps aux \| grep target_name \| grep -v grep \| tr -s ' ' \| cut -d ' ' -f2`

This iterates through process IDs. Replace target_name with the condition string you want to filter on to find the desired processes.

Set line

line=`ps --pid ${pid} -eo pid,etimes | grep ${pid}`

1	line=`ps --pid ${pid} -eo pid,etimes \| grep ${pid}`

Outputs the PID and etimes and retrieves the line for the specified PID.

Set duration

duration=`cut -d' ' -f 2 <<< ${line}`

1	duration=`cut -d' ' -f 2 <<< ${line}`

Extracts the execution time from the ps result. The time is in seconds.

-z $duration

if [ -z $duration ]
then
continue
fi

if [ -z $duration ]

then

continue

If there is no process, it moves on to the next iteration.

$duration -ge 345600

if [ $duration -ge 345600 ]
then
echo $duration
sudo kill $pid
fi

if [ $duration -ge 345600 ]

then

echo $duration

sudo kill $pid

If the process has been running for more than 345,600 seconds (4 days), it terminates it. It does so using sudo kill $pid.

The Life

Shell: Terminating Long-Running Processes

Code

Explanation

for Loop

Set line

Set duration

-z $duration

$duration -ge 345600

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