[SOLVED] egrep gives me what I want, grep -E does not

Issue

I have read that egrep is deprecated in favour of grep -E so I'm looking back at my code and changing it where I find it. But I see that the results are not always as expected.

With egrep, I get my list of running Oracle instances:

ps -ef|grep [p]mon|awk -F'ora_pmon_' '{print $NF}'|egrep -v 'ASM|^$'
halana
bila
halsasa
loana

However with grep -E, I get part of the awk in the results:

ps -ef|grep [p]mon|awk -F'ora_pmon_' '{print $NF}'|grep -Ev 'ASM|^$'
halana
bila
halsasa
 {print $NF}
loana

Excluding 'print' obviously works but is it the right way to go about it?:

ps -ef|grep [p]mon|awk -F'ora_pmon_' '{print $NF}'|grep -Ev 'ASM\|^$|print'
halana
bila
halsasa
loana

Is this effect due to the fact that grep -E allows additional regular expression syntax?

Solution

Suggesting to simplify your line, eliminate all grep commands:

pgrep -af 'pmon'|awk -F'ora_pmon_' '!/ASM|^$/{print $NF}'

Fold first grep command into pgrep command.

Fold second grep command into awk scirpt !/ASM|^$/{print $NF}

Answered By - Dudi Boy

Answer Checked By - David Marino (WPSolving Volunteer)