Linux Recipes

Contents 1 Useful output from du 2 assign a multiline variable in linux bash unix 3 getting the pid of a process by something contained on its command line. 4 keeping track of open files

Useful output from du

getting du to just list child directory sizes

[~]$ sudo du -h --max-depth=1 /home/
1.5M    /home/booboo
28K     /home/logs
8.2M    /home/fishmonger
104K    /home/whence
16K     /home/lost+found
916K    /home/nestor
330M    /home/reassembler
283M    /home/werner
344K    /home/layabout
623M    /home/
[~]$

assign a multiline variable in linux bash unix

# define extra args for monitoring
JCONSOLE_ARGS='
-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=8004
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-XX:+HeapDumpOnCtrlBreak
-XX:+HeapDumpOnOutOfMemoryError
 ' # this line begins with a apace, ' ' and a quote, "'", please leave it that way


the important bits here are the quotes that start and end the assignment, the new lines are turned into spaces

getting the pid of a process by something contained on its command line.

example:
sudo jstat -gc -t `sudo jps|grep -i bootstrap|gawk '{print $1}'`;


explanation:
there are 4 parts to the command above.
    sudo jps          # get all java pids
    grep -i bootstrap # look for the on that has the word bootstrap in its command
    gawk '{print $1}' # parse into fields and print the first field, that's the pid

    sudo jstat -gc -t # run the jstat command against the pid 

keeping track of open files

cronned this job to count open files

#!/bin/bash

DATE=$(date +"%Y%m%d%H%M")

LINES=`sudo /usr/sbin/lsof`

LINE_FILE=oflistfiles/open_file_list_$DATE.txt

echo "$LINES" >>$LINE_FILE

LOG_FILE=openfiles.log

# log open tcp connections
TCP=`sudo /usr/sbin/lsof|grep TCP|wc -l`

# log regular open files
REGULAR=`sudo /usr/sbin/lsof|grep REG|wc -l`

# all files
ALL=`sudo /usr/sbin/lsof|wc -l`



LINE=`date`" - TCP($TCP), REG($REGULAR), ALL($ALL) - $LINE_FILE"
echo $LINE >>$LOG_FILE


-- produces a log file like this:

Mon Jan 18 13:33:02 EST 2010 - TCP(159), REG(2856), ALL(3738) - oflistfiles/open_file_list_201001181301.txt
Mon Jan 18 13:34:02 EST 2010 - TCP(164), REG(2896), ALL(3788) - oflistfiles/open_file_list_201001181301.txt
Mon Jan 18 13:35:01 EST 2010 - TCP(175), REG(2856), ALL(3754) - oflistfiles/open_file_list_201001181335.txt
Mon Jan 18 13:36:03 EST 2010 - TCP(179), REG(2794), ALL(3669) - oflistfiles/open_file_list_201001181336.txt