Linux commnads while troubleshooting Oracle Apps

Enable Trace on any Executable to find out whats happening at O.S. Level

truss -eafl -o output.trc -o truss.txt
for example for Apache
truss -eafl -o output.trc -o truss.txt apachectl

This command will trace any system calls and will help you to find out errors.



How to find a "word" or pattern in all files in a directory & subdirectories

find . -name "*" -exec grep -l {} \; -print
for example I want to search for word oracle
find . -name "*" -exec grep -l oracle {} \; -print



How to delete files older than N number of days , Useful to delete old log files

find . -name '*.*' -mtime + -exec rm {} \;
for example if I want to delete all files older than 7 days
find . -name '*.*' -mtime +7 -exec rm {} \;
*Check carefully & run it first from logs or dump directory


How to find a class inside a set of Jar files


for i in 'find .-name *.jar'
do
if test 'jar -tvf $i|grep QualityObject.class'
then
ls $i
fi
done


How to find the symbolic links that point to the old path in your oracle_home and appl_top.

This command is useful in cloning after restore from source to target that symbolic link are not pointing to source.

ls -al `find . -type l` | grep $OLD_PATH



To find all the text files that contains the old path at the UNIX level.

find . -type f -print|grep -v ":"|xargs file|grep "text"|awk '{FS=":"}{print $1}'|xargs grep -il $OLD_PATH



How to Sort files based on Size of file in a Directory
Useful in finding out spaces issues

ls -l | sort -nrk 5 | more


How to check if a Port is listening for any Service

netstat -an | grep $PORTNO

How to schedule a Job in Unix

Use cronjob
crontab -l ( list current jobs in cron)
crontab -e ( edit current jobs in cron )
_1_ _2_ _3_ _4_ _5_ $Job_Name
1 - Minutes (0-59)
2 - Hours ( 0-24)
3 - day of month ( 1- 31 )
4 - Month ( 1-12)
5 - A day of week ( 0- 6 ) 0 -> sunday 1-> monday
e.g. 0 0 1 * 5 Means run job at Midnight on 1st of month & every friday