Invoking system(cmd) inside awk command


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Invoking system(cmd) inside awk command
# 1  
Old 12-30-2013
Invoking system(cmd) inside awk command

Hi,

I was searching for a way to grep 2 lines before and after a certain keyword, and I came across the following code..

Code:
awk "\$0 ~ /ORA-/ { 
cmd=\"awk 'NR>=\" NR-2 \" && NR<=\" NR+2 \"' init.ora\"
system(cmd)
}" input_file

I could not understand how this works. What is system() ? what does that do? Can someone please help me understand what the above command does? Curious to know.

Thanks.

Last edited by Kulasekar; 12-30-2013 at 06:14 PM.. Reason: awk, context grep, system, invoking functions in awk
# 2  
Old 12-30-2013
system(expression) executes the command given by expression and return the exit status of the command.

The awk program that you posted is looking for a pattern ORA- in the file: input_file

Once found, it is prints records between NR-2 && NR+2 from file: init.ora

NR is current input record # with pattern ORA- in the file: input_file

You can put a print statement to understand what is going on:
Code:
print cmd
system(cmd);

# 3  
Old 12-31-2013
What would be the input file? To me, that script made sense only if input_file actually is init.ora.
Did you consider grep's -A and -B options?
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

awk trouble inside another command

I tried running this. dsh -w server1 'lsof /audit | awk '{ print $2 }'' It did not like above so I tried to escape the single parenthesis at the end. dsh -w server1 'lsof /audit | awk '{ print $2 }\'' It then hung so I changed up the parenthesis to this. This worked. dsh -w server1... (6 Replies)
Discussion started by: cokedude
6 Replies

2. Shell Programming and Scripting

Using sed inside system call in awk

HI , I am trying to write a code where if a file system has / at the end then replace it with null but it should not affect root file system / for example if ip is /var/opt/home/ then o/p is /var/opt/home but if ip is / then it should remain /. for this i am using below code but no success... (8 Replies)
Discussion started by: Jcpratap
8 Replies

3. Shell Programming and Scripting

Command in inside awk statement

Hello can you please help me with below script which is meant to delete clients from multiple netbackup policies I want to run a command insdie awk statement apparelnlty this script is not working for me for i in $( cat clients_list) do bppllist -byclient $i | awk... (6 Replies)
Discussion started by: Sara_84
6 Replies

4. Shell Programming and Scripting

Grep command inside awk

Hi, I would like to use grep command inside awk. Here is my requirement below : file.txt col1 col2 col3 col 4 col 5 wrxwrx 124 jun 3 Sensex.EMEA wrxwrx 120 jun 4 Emex.US wrxwrx 130 feb 3 passion.AUS wrxwrx 145 feb 9 lession.AUS wrxwrx 130 feb 5 pass.US wrxwrx 130 feb 8... (5 Replies)
Discussion started by: Balasankar
5 Replies

5. Shell Programming and Scripting

Help in using date command inside awk

Hi All, bash-3.2$ autorep -J BOX_NAME% -l0 | grep BOX_NAME| awk -f awkScript.awk sh: -c: line 0: unexpected EOF while looking for matching `"' sh: -c: line 1: syntax error: unexpected end of file BOX_NAME SU 06/21/2013 03:44:03 06/21/2013 07:46:37 0 #My awkfile { ... (3 Replies)
Discussion started by: ddspark
3 Replies

6. Shell Programming and Scripting

Multiple command execution inside awk command during xml parsing

below is the output xml string from some other command and i will be parsing it using awk cat /tmp/alerts.xml <Alert id="10102" name="APP-DS-ds_ha-140018-componentFailure-S" alertDefinitionId="13982" resourceId="11427" ctime="1359453507621" fixed="false" reason="If Event/Log Level(ANY) and... (2 Replies)
Discussion started by: vivek d r
2 Replies

7. Shell Programming and Scripting

Not correct processing of “\ “ in names of dirs inside shell script (tar command - system backup scr

Hello, Recently, I've started with shell scripting, and decided to write a script for my system backup using tar. When I was dealing with tar execution inside shell script I found this, inside shell we have the following code: tar $TAR_PARAMS $ARCHIVE_FILE $EXCLUDE $BACKUP_STARTwith... (6 Replies)
Discussion started by: ilnar
6 Replies

8. Shell Programming and Scripting

How to use same variable value inside as well as outside of the awk command?

Hi Jim, The following script is in working state. But i m having one more problem with awk cmd. Could you tell me how to use any variable inside awk or how to take any variable value outside awk. My problem is i want to maintain one property file in which i am declaring variable value into that... (12 Replies)
Discussion started by: Ganesh Khandare
12 Replies

9. Shell Programming and Scripting

Capturing awk's system(cmd) output

Hi everybody, I am working on a bigger awk script in which one part is comparing the size of two files. I want to evaluate which file is bigger and then just save the bigger one. I got it all working except for the part where I want to figure out which file is bigger; the one awk is currently... (2 Replies)
Discussion started by: iMeal
2 Replies

10. Shell Programming and Scripting

Running command inside awk

Hi, I have a awk script to read a CSV file. After reading the values i want to call a executable (nameely call_it) with the values what i read from the scv file. I dont want to use system command inside the awk. Is there any other way to run the executable from the awk script Thanks ... (1 Reply)
Discussion started by: Raghuram.P
1 Replies
Login or Register to Ask a Question