Using awk in UNIX & Linux Oracle Tips by Burleson Consulting

Also see handy awk command examples.

Using awk in UNIX

The awk utility is especially useful for removing a specific column of output from a UNIX command. For example, suppose we need to create a list of UNIX process ID’s for all Oracle processes on our server.

root> ps -ef|grep -i oracle|awk '{ print $2 }'
23308
25167
12193
25163
12155
24065
24073

Here we start by issuing the ps –ef command to get a list of all UNIX processes, and then use grep to filter out all processes except this that contain the string “oracle.

Finally, we use the awk utility to extract the second column of output.

root> ps -ef|grep -i oracle
oracle 23308 1 0 May 14 ? 0:06 ora_lgwr_prodb1
oracle 25167 1 0 Apr 30 ? 0:26 ora_smon_prodc1
oracle 25163 1 0 Apr 30 ? 41:27 ora_lgwr_prodc1
oracle 12155 1 0 11:30:43 ? 0:01 oracleprodcars (LOCAL=NO)
oracle 24065 1 0 Apr 30 ? 0:02 ora_pmon_rman
oracle 24073 1 0 Apr 30 ? 10:39 ora_ckpt_rman
oracle 24846 1 0 May 11 ? 0:48 oracleprodc1 (LOCAL=NO)

root> ps -ef|grep -i oracle|awk '{ print $2 }'

23308
25167
12193
25163
12155
24065
24073

The awk  utility is used often extract a specific column of data from output or a file.  For example, to create a list of UNIX process IDs for all Oracle processes on the server.

root> ps -ef|grep -i oracle|awk '{ print $2 }'

23308
25167
12193
25163
12155
24065
24073

First, issue the ps  –ef  command to get a list of all UNIX processes, and then use grep to filter out all processes except this that contain the string “oracle.”  The awk  utility is used to extract the second column of output.

root> ps -ef|grep -i oracle

  oracle 23308     1  0   May 14 ?        0:06 ora_lgwr_prodb1
  oracle 25167     1  0   Apr 30 ?        0:26 ora_smon_prodc1
  oracle 25163     1  0   Apr 30 ?       41:27 ora_lgwr_prodc1
  oracle 12155     1  0 11:30:43 ?        0:01 oracleprodcars (LOCAL=NO)
  oracle 24065     1  0   Apr 30 ?        0:02 ora_pmon_rman
  oracle 24073     1  0   Apr 30 ?       10:39 ora_ckpt_rman
  oracle 24846     1  0   May 11 ?        0:48 oracleprodc1 (LOCAL=NO)

root> ps -ef|grep -i oracle|awk '{ print $2 }'

23308
25167
12193
25163
12155
24065
24073