topic Re: scripting - read vars from a file in Operating System - HP-UX

scripting - read vars from a file

Kim Kendall — Mon, 23 Dec 2002 17:37:03 GMT

Trying to read data from a file. First part of the script outputs ps info to a file:

UNIX95= ps -e -o ruser,pid,pcpu,vsz,stime,time,args | grep oracleprod | grep -v grep | sort -rnk3 >> ./ps.out

Now I want to do a "for i in `cat ./ps.out`" , BUT, every field is on it's own line in the output file. If I cat the file, or even vi the ps.out file, it appears to be fine, as I would expect it to be.

So I either need to find a way to read 7 lines at a time and assign them to different variables, or find a way to fix the formatting of the ps command so it writes the lines correctly.

Any ideas?

Re: scripting - read vars from a file

James R. Ferguson — Mon, 23 Dec 2002 17:46:40 GMT

Hi Kim:

To read one line at a time from your file, simply do:

while read LINE
do
your_thing
done < ps.out

...If you want to read the seven fields comprising each line, do:

while read RUSER PID PCPU VSZ STIME TIME ARGS
do
your_thing
done < ps.out

Regards!

...JRF...

Re: scripting - read vars from a file

Kim Kendall — Mon, 23 Dec 2002 17:51:27 GMT

It's 7 fields repeated over and over

Re: scripting - read vars from a file

Mark Greene_1 — Mon, 23 Dec 2002 18:12:35 GMT

You have several choices (but then it's unix, so you already knew that). Unless you need to retain the results in a file you set UNIX95 seperately from the command (export UNIX95=1, I think will work) and route the output of the ps query to a variable like this:

PS_OUT=`ps -e -o ruser,pid,pcpu,vsz,stime,time,args | grep oracleprod | grep -v grep | sort -rnk3`

(watch the line wrap, all that goes on 1 line)

Next, change the IFS variable to cooperate:

OLD_IFS=$IFS
IFS="^J" (that's a control-J, a linefeed only)

Now this construction will give you an entire line at a time:

for LINE in `echo PS_OUT`; do
[do your stuff with the data here]
done
IFS=$OLD_IFS

The other option you have is leave the ps capture the way you have it and to read from the ps.out file like this:

exec 4<./ps.out
while read -u4 LINE; do
[do your stuff with the data here]
done

Depending on the actual format of the file, you may need to alter the IFS variable as above.

HTH
mark

Re: scripting - read vars from a file

Steven E. Protter — Mon, 23 Dec 2002 19:11:31 GMT

A helpful hint with UNIX95 variable.

Don't set it to 1 in /etc/profile or root profile

Havint it set when you sh HP depots can cause crc errors. Not really, but you won't be able to use the patch.

Steve

Re: scripting - read vars from a file

Oleg Zieaev_1 — Mon, 23 Dec 2002 22:07:14 GMT

Hello.
If you have predefined fields in your file do:

while read -r RUSER PID PCPU VSZ STIME TIME AGRS
do
.... use your $RUSER etc variables here as you want.
done < ./ps.out

Hope this helps,
0leg

Re: scripting - read vars from a file

Fred Martin_1 — Thu, 26 Dec 2002 21:10:07 GMT

You might use awk, but I suspect if you knew the awk language you would have thought of that already. awk reads files one line at a time and uses white space as a field seperator.

For example, the output from a 'ps' command might look like this:

gbc 18685 1 0 14:56:03 pts/ta 0:00 /usr/bin/newmail -i90

If you pipe that to awk, within awk each field on the line is assigned a parameter variable:

$0 = the entire line
$1 = gbc
$2 = 18685
$3 = 1
$4 = 0
$5 = 14:56:03
$6 = pts/ta
$7 = 0:00
$8 = /usr/bin/newmail
$9 = -i90

Anyway I can't give you an awk tutorial here but if you already know some shell scripting stuff, you can handle awk. The best book about the language is "The Awk Programming Language" by Aho, Kernighan and Weinberger.

Re: scripting - read vars from a file

Fred Martin_1 — Thu, 26 Dec 2002 21:13:18 GMT

...but I also like the "while read line" solution above....
Fred

Re: scripting - read vars from a file

Wodisch_1 — Thu, 26 Dec 2002 23:37:28 GMT

Hi,

looks like your more after the part inside the loop?
How about using the POSIX features of "ps", and suppressing the headline:

UNIX95=. ps -e -C your,processes,go,here -o ruser=,pid=,pcpu=,vsz=,stime=,time=,args= |
while read ruser pid pcpu vsz stime time args
do case "$ruser" in
process#1) do-something-here ;;
process#2) do-something-else ;;
esac
done

FWIW,
Wodisch

Re: scripting - read vars from a file

Kim Kendall — Fri, 27 Dec 2002 17:15:32 GMT

Ended up using Mark Greene's idea...

exec 4<$psout2
while read -u4 LINE
do
_usr=`echo $LINE | awk '{print $1}'`
_pid=`echo $LINE | awk '{print $2}'`
_cpu=`echo $LINE | awk '{print $3}'`
_vsz=`echo $LINE | awk '{print $4}'`
_sti=`echo $LINE | awk '{print $5}'`
_tim=`echo $LINE | awk '{print $6}'`
_arg=`echo $LINE | awk '{print $7}'`

done

Not exceptionally elegant, but it works! ;)