topic Re: grep command in Operating System - HP-UX

grep command

Tarek — Wed, 18 Jul 2001 07:54:36 GMT

I work on hp systems. I want to find some entries in the /etc/hosts. I wrote a script, but while i issue the grep command i have some problems.
For example if i make grep hp1 /etc/hosts i will see all ws that begins with hp1 so also hp12, hp110, hp19 and so on..
I want to find only hp1. I know that with sun the command is grep -w, but this doesn't exist on hp, what is it's correspondance? I looked in the grep's man, but i didn't find it. (maybe i didn't look well!!)

Re: grep command

Laurent Paumier — Wed, 18 Jul 2001 08:14:29 GMT

You could replace the grep command with perl. Perl has a smarter regexp syntax :

# perl -ne '/\bhp1\b/ && print' /etc/hosts

(\b stands for word boundary)

Re: grep command

Alexander M. Ermes — Wed, 18 Jul 2001 08:18:09 GMT

Hi there.
Try this :

grep 'hp1 ' /etc/hosts

Rgds
Alexander M. Ermes

Re: grep command

Tarek — Wed, 18 Jul 2001 08:27:52 GMT

Thanks to both!! But i have still a problem. How can i implement your code in the script.
#!/sbin/sh
echo > /tmp/list
for i in 'cat /tmp/hplist'
do
grep $i /etc/hosts >> /tmp/list
done
I saw that if i put $i between '$i ', the output is wrong.

Re: grep command

federico_3 — Wed, 18 Jul 2001 08:34:43 GMT

I'd do like the following :

grep hp1$ /etc/hosts

Re: grep command

federico_3 — Wed, 18 Jul 2001 08:45:00 GMT

#!/sbin/sh
echo > /tmp/list
for i in 'cat /tmp/hplist'
do
grep $i$ /etc/hosts >> /tmp/list
done

Re: grep command

Thierry Poels_1 — Wed, 18 Jul 2001 08:50:58 GMT

hi,
grep "$i " ...
instead of
grep '$i ' ...
With single quotes your variable will not be translated, and grep will search for $i (dollar-i) in your file.
regards,
Thierry.

Re: grep command

Tarek — Wed, 18 Jul 2001 09:44:30 GMT

The "$i " and $i$ works so and so. The problem is that they don't search every entry that i have in the list in /etc/hosts.
So the script isn't helpful.

Re: grep command

Robin Wakefield — Wed, 18 Jul 2001 10:11:03 GMT

grep -e "$i[ ]" -e $i$ /etc/hosts

where you type space followed by tab in the square brackets.

If this doesn't work, what type of expression is not being captured?

Robin.

Re: grep command

Robin Wakefield — Wed, 18 Jul 2001 10:19:50 GMT

...or try this too:

grep -E "$i( | |$)" /etc/hosts

again, it's space,pipe,tab,pipe,dollar in the brackets.

Robin.

Re: grep command

Tracey — Wed, 18 Jul 2001 10:59:08 GMT

The hostnames in my hosts file usually have a tab after the name. The following works for me:

grep "hp1[ ]" hosts

The first character in the brackets is a space, the second character is where I pressed the tab key (on my system it actually show many more spaces) That way it will get those that end in spaces or those that end in a tab character.

Re: grep command

Laurent Paumier — Wed, 18 Jul 2001 11:31:41 GMT

How about rewriting the whole script ?
Here's what you could du using awk :

awk '
BEGIN {
while (getline <"/etc/hosts") {
for (i=1;i<=NF;i++) {
host[$i]=$0
}
}
while (getline <"/tmp/hplist") {
printf("%s\n",host[$0])
}
}' >/tmp/list

Re: grep command

Tarek — Wed, 18 Jul 2001 11:55:51 GMT

That's it Robin!!! The second code was the right one.
I tried also yours Laurent, it works, but there are some entries that aren't found.
However i'd like to learn something about using awk, it seems very powerful, is there some tutorial on the net?
Thanks both, and of course thanks to all for your kindly help.
Regards
Tarek

Re: grep command

Robin Wakefield — Wed, 18 Jul 2001 12:26:35 GMT

Tarek, try:

http://vectorsite.tripod.com/tsawk0.html

Robin