Setting multiple switches in grep (bash script)

Porch · 02-21-2010, 03:03 PM

Hello,
My first post!

Without posting my whole long script, i'm working on setting multiple switches in grep.

Here's an example of how to run my script:
scriptname root daemon

would (should) produce the results of this:
ps aux | grep -i -e root -e daemon
(I could have 1 input, a thousand inputs, etc.)

Right now i have some code to catch the inputs, using a variable "z":

Code:

z=""

[Code to catch inputs, for each input:]
z="${z} -e ${1}"
shift 1
;;

Then:

Code:

ps aux | grep -i $z

I'm almost positive that the problem is in the bolded line above (for one thing, it always leaves off the initial "-e"). So basically i want a string that gives me "-e input" and concatenates as many times as necessary.

I've been working on this darn thing all morning and it's the last hurdle before i turn this assignment in!
Thanks in advance for the help!
~Chris

micxz · 02-21-2010, 03:59 PM

How about something like:

for each $#;
do ps aux | grep -i $1 , $2 , $3 and so on..

Porch · 02-21-2010, 04:04 PM

That's a good thought, but to be honest i left out a little bit of my assignment. My actual command line usage is this:

scriptname [patterns] [-t seconds] [-n count]

So it is possible that $2, $3, etc. may be related to the "time" or "count" functions. Thanks though

unSpawn · 02-21-2010, 04:06 PM

In your case you may want to string together all search terms, replace spaces with pipe sign then egrep for it: 'SEARCH_TERMS="${SEARCH_TERMS} $NEW_SEARCH_TERM"; "${SEARCH_TERMS}=${SEARCH_TERMS// /|}"; ps|egrep -i "(${SEARCH_TERMS})";'? But instead of using 'ps aux | grep' why not use 'pgrep'? 'pgrep' with "-f" accepts multiple search terms like '(term0|term1)' and can grep for UIDs as well so you can 'pgrep -lU root -f '(kj|bin)';'. As for the parameters see 'getopts'?

Porch · 02-21-2010, 04:33 PM

Thanks, unspawn! I think i'm headed in the right direction.

To answer your question, i can't use pgrep because i don't know if the input is going to be a user, or a process, or...? It could be anything!

But the rest of your response makes perfect sense, and replacing the spaces with a | is a great idea, thanks! I'm having some problems getting grep or egrep to take a search in the form (this|that|someother), though. It looks like it's been deprecated?

UPDATE: Okay, i got it working using:

Code:

egrep 'this|that'

Fixing other little things here and there, will get back to you when i'm finished

EDIT: D'oh. Okay, so i changed that to

Code:

egrep "this|that"

...because passing it as egrep '${z}' passes ${z} instead of this|that.

Also, i ran into a problem where the first blank character was being converted to a pipe as well, and found the following code to fix that:

Code:

var="${var#"${var%%[![:space:]]*}"}"

Thanks again!!

chrism01 · 02-21-2010, 05:14 PM

Definitely getopts as per UnSpawn