topic Re: strange behavior using grep command in Operating System - HP-UX

strange behavior using grep command

SwissKnife — Thu, 23 Sep 2021 11:47:41 GMT

Hi,

here is my input file

sanvg1::::lv_logiciel /logiciel
sanvg1::::loglv00 N/A
sanvg1::::lv_oradiag /logiciel/app/oracle/diag
sanvg1::::lv_exp0x00 /exp0x00
sanvg1::::lvbase /base

I need to grep /logiciel

but

cat myfile | grep -w "/logiciel"

returns /logiciel but also /logiciel/app/oracle/diag

How to grep the exact substring ?

Thanks in advance,

Kind regards,

Den.

Re: strange behavior using grep command

Duncan Edmonstone — Thu, 23 Sep 2021 10:40:01 GMT

Here's the man page for the -w option of grep:

-w Select only those lines containing matches that form whole words. The test is that the matching substring must either be at the beginning of the line, or preceded by a nonword constituent character. Similarly, it must be either at the end of the line or followed by a non-word constituent character. Word-constituent characters are letters, digits, and the underscore.

So "/" is a "non-word consituent character", so it is considering the "/logiciel" part to be a seperate word from "/app/oracle/diag" (which it would also consider seperate words)

Quick and dirty fix I guess would be that as you know the field you want to match on is at the end of the line you could instead use

grep "/logiciel$" myfile

Re: strange behavior using grep command

SwissKnife — Thu, 23 Sep 2021 11:59:17 GMT

Hi Duncan,

Thank you so much.

Not so dirty!

In fact my code is now something like that, so I tested your trick and it works.

VG=`echo "$theLVlist" | grep -w "${FS}$" | awk -F "::::" '{print $1}'`

Kind regards,

Den.