A question about "grep" command

[Herath]

I am learning regular expressions these days. And I tried the following code in order to isolate the firefox process from the process list of "ps -A".

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ps -A|grep ^f

But it does not give any output. Or any error. I do not seem to able to figure out the problem.

Anyway,

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ps -A|grep f

would just show the names of the process of which contain "f" in their name. But can't get the ones starting with "f" using the "^f" regexp.

Any idea?.

[SemiconductorCat]

^ - means start of a every line.

There is a ps -a option for all. But I didn't find a -A option in the man page.
Typically it prints the PID at the start of line.So that's why it won't work.


Are you want firefox process id to kill it? then

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$ ps -a | grep firefox-bin 

There is a column parse method using sed. But I'm not aware of it well. Somebody else will
post it for you.

[Herath]

No I am not trying to kill firefox process or anything. I am just wanting to try that regular expression. To get the list of all items starting with "f".

scr.png (139.07 KiB) Viewed 8490 times

And output from "ps -A"

psOutput.txt

(5.14 KiB) Downloaded 625 times

[SemiconductorCat]

so as I said you have to take the 4th column.

I could post the code here. But I'm not aware of it.

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 ps -a | sed 's/\|/ /' | awk '{print $8}' | grep ps

In my cygwin.Sorry I have a assignment to do , can't reboot.

as I told you before , I don't know how it work.

[Herath]

OK. Got it. it should be due to grep looking only at line beginings.

sed edits the stream so awk can seperate them, you have then printed the 8th column, and grep takes it. The answer for my case would be.

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ps -A|sed 's/\|/ /'|awk '{print $4}'|grep ^f