Unix for DBA

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Below are some of the basic unix commands which will be useful for Oracle DBA.

How to kill all similar processes with single command (in this case opmn)

ps -ef | grep opmn |grep -v grep | awk ‘{print $2}’ |xargs -i kill -9 {}

Locating Files under a particular directory

find . -print |grep -i test.sql

Using AWK in UNIX

To remove a specific column of output from a UNIX command – for example to determine the UNIX process Ids for all Oracle processes on server (second column)

ps -ef |grep -i oracle |awk ‘{ print $2 }’

Changing the standard prompt for Oracle Users

Edit the .profile for the oracle user

PS1=”`hostname`*$ORACLE_SID:$PWD>”

Display top 10 CPU consumers using the ps command

/usr/ucb/ps auxgw | head -11

Show number of active Oracle dedicated connection users for a particular ORACLE_SID

ps -ef | grep $ORACLE_SID|grep -v grep|grep -v ora_|wc -l

Display the number of CPU’s in Solaris

psrinfo -v | grep “Status of processor”|wc -l

Display the number of CPU’s in AIX

lsdev -C | grep Process|wc -l

Display RAM Memory size on Solaris

prtconf |grep -i mem

Display RAM memory size on AIX

First determine name of memory device

lsdev -C |grep mem

then assuming the name of the memory device is ‘mem0’

lsattr -El mem0

Swap space allocation and usage

Solaris : swap -s or swap -l

Aix : lsps -a

Total number of semaphores held by all instances on server

ipcs -as | awk ‘{sum += $9} END {print sum}’

View allocated RAM memory segments

ipcs -pmb

Manually deallocate shared memeory segments

ipcrm -m ‘<ID>’

Show mount points for a disk in AIX

lspv -l hdisk13

Display amount of occupied space (in KB) for a file or collection of files in a directory or sub-directory

du -ks * | sort -n| tail

Display total file space in a directory

du -ks .

Cleanup any unwanted trace files more than seven days old

find . *.trc -mtime +7 -exec rm {} \;

Locate Oracle files that contain certain strings

find . -print | xargs grep rollback

Locate recently created UNIX files (in the past one day)

find . -mtime -1 -print

Finding large files on the server (more than 100MB in size)

find . -size +102400 -print

Crontab :

To submit a task every Tuesday (day 2) at 2:45PM

45 14 2 * * /opt/oracle/scripts/tr_listener.sh > /dev/null 2>&1

To submit a task to run every 15 minutes on weekdays (days 1-5)

15,30,45 * 1-5 * * /opt/oracle/scripts/tr_listener.sh > /dev/null 2>&1

To submit a task to run every hour at 15 minutes past the hour on weekends (days 6 and 0)

15 * 0,6 * * opt/oracle/scripts/tr_listener.sh > /dev/null 2>&1

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