unix command line, grep a command line command's output in a script

Code:

---

#!/bin/bash


if grep -q Safari.app `pa ax`; then
    echo found
else
    echo not found
fi

---

Really clueless on scripts. Goal: run the command line call
pa ax
which'll give all the running processes, then grep for "Safari.app" in it and do something if found. Any ideas? Thanks.

Try
pa ax | grep -q Safari.app

(Oops, first, correction of me: it's 'ps ax' not 'pa ax')

Hi, thanks for the suggestion. That works on the command line, but I don't know how it should be used in a script. I tried:

Code:

---

#!/bin/bash

if ps ax | grep -q Safari.app; then
    echo found
else
    echo not found
fi

---

which seemingly worked (output found when Safari was running), but then I changed 'Safari.app' to 'SafaXXri.app' and it still said found. Any suggestions? Thanks.

Oh, I've worked out why. On the command line this
ps ax | grep Safari.app
outputs
54882 ?? S 39:17.90 /Applications/Safari.app/Contents/MacOS/Safari -psn_0_24999894
58634 s001 R+ 0:00.00 grep Safari.app
two positive hits, two lines, one of which is the grep itself! So
ps ax | grep SafXari.app
on the command line outputs
58632 s001 S+ 0:00.00 grep SafXari.app
So it doesn't matter what you put there, it's always going to find one posative hit at least. So the problem isn't the way I've used the line in the script.
So I suppose the question is, and it's probably quite a simple answer, how to filter out
58632 s001 S+ 0:00.00 grep SafXari.app
like lines from the grep output?
Thanks.

Use a different tool perhaps?

Code:

---

$ ps ax | grep firefox
 2305 ?        Sl    1:43 /usr/lib/firefox/firefox
 3725 pts/4    S+    0:00 grep --color=auto firefox
$ pgrep firefox
2305

---

pgrep knows to exclude itself.

Tried that but my command line hasn't got that command/tool.

Maybe

Code:

---

$ ps ax | awk '$5 ~ /firefox/'
 2305 ?        Sl    17:58 /usr/lib/firefox/firefox

---

OK, thanks, but that doesn't work in the if situation! I looked in awk's manual page, having looked in grep's manual page to see what q meant, but couldn't see a quiet / silent option for awk. How to use awk in that if line?

Or, how to assign the output of ps ax to a variable, then grep that variable, like what I'm trying to do here but what isn't working at all?:

Code:

---

#!/bin/bash


var = ps ax
if var | grep -q Safari.app; then
    echo found
else
    echo not found
fi

---

Code:

---

$ var=$(ps ax)
$ echo $var | grep -q firefox
$ echo $?
0
$ echo $var | grep -q zarniwoop
$ echo $?
1

---

You can then write

Code:

---

if [ $? -eq 0 ]; then
else
fi

---

Code:

---

var=$(ps ax)
echo $var | grep -q safari
echo $?




if [ $? -eq 0 ]; then
    echo found
else
    echo not found
fi

---

outputs:
1
found

Then putting safaXXri for the search, it still outputs:
1
found

I have no idea what's going on! :)

I guess this isn't possible in a script? edit: sorry, feeling a bit defeatist this morning

You're testing the result of echo $?, not the result of grep.

Code:

---

$ echo $var | grep -q zarniwoop
$ if [ $? -eq 0 ]; then echo yes; else echo no ; fi
no
$ echo $var | grep -q firefox
$ if [ $? -eq 0 ]; then echo yes; else echo no ; fi
yes

---

Ah, yup, that's working, many thanks Salem.