topic Re: Awk - help in Operating System - Linux

Awk - help

Senthil Prabu.S_1 — Tue, 17 Apr 2007 08:16:23 GMT

Hi,
I have a script to match a list of patterns defined in array and do some operation. The flow is "array elements are passed into a while loop, where pattern matching on individual elements using awk". It works fine when array element have single "/" like "/var", but awk fails when array element have two slaces like "/global/TspOam".

I knew special characters can be given in "[ ]" to match the pattern, but it didnot help me.

My script looks like this;
#!/usr/bin/ksh -x
set -A filesys /var

i=0
while [ $i -lt ${#filesys[@]} ]
do
position_params=`awk ${filesys[$i]}[\^\/]/'{print}' test.txt | grep -v '^[ ]*#'`
echo $position_params
((i=i+1))
done
........it goes on

When array is populated with elements like "/global/TspOam", awk fails inside the while loop.

Can anyone help me....

Note:
Running on solaris 10 OS...

Thanks,
Prabu.S

Re: Awk - help

Peter Nikitka — Tue, 17 Apr 2007 09:15:28 GMT

Hi,

on Solaris boxes I generally do not recommend to use plain 'awk' - it's normally an ancient version:
ls -goi /usr/bin/*awk
26691 -r-xr-xr-x 2 89128 Jan 8 19:30 /usr/bin/awk
26694 -r-xr-xr-x 1 126964 Jan 8 19:30 /usr/bin/nawk
26691 -r-xr-xr-x 2 89128 Jan 8 19:30 /usr/bin/oawk

Just try first
nawk (= /usr/bin/nawk)
then
/usr/xpg4/bin/awk

Next - which is NOT Solaris specific stuff:
- there's no need for grep - awk can do it by itself much more efficient. I guess you want to drop lines commented out by this.
- your awk-command is really doubtful, because match operator and your pattern itself get mixed up. Having no 'test.txt' I can only guess what result you want to get, however.

Try this (
I use the match operator and set a variable 'pat' to clarify the pattern):

#!/usr/bin/ksh -x
set -A filesys /var /usr/bin

typeset -i i=0
while [ $i -lt ${#filesys[@]} ]
do
position_params=$(nawk -v fsys=${filesys[$i]} 'BEGIN {pat="^"fsys"[^/]*"}
/^[ ]*#/ {next}
$0 ~ pat {print}' test.txt)
echo $position_params
((i=i+1))
done

mfG Peter

Re: Awk - help

Senthil Prabu.S_1 — Wed, 18 Apr 2007 00:23:29 GMT

Hi,
My test.txt will have lines containing patterns /var, /globa/Tsp...etc.[hard-coded in array] when these are matched, then they should be stored in the variable "position_params".

But your script didn't store the patterns in the variable position_params. It outputs nothing.

Can you help....

Prabu.S

Re: Awk - help

Arturo Galbiati — Wed, 18 Apr 2007 03:05:59 GMT

Hi Prabu,
why awk and not simply grep?
This runs fine on my HP-UX11i:
set -A filesys /var /globa/Tsp
typeset -i i=0
while [ $i -lt ${#filesys[@]} ]
do
position_params=$(grep ${filesys[$i]} test.txt)
echo $i $position_params
((i=i+1))
done

0 /var
1 /globa/Tsp

cat test.txt
/var
/globa/Tsp

HTH,
Art

Re: Awk - help

Peter Nikitka — Wed, 18 Apr 2007 04:23:38 GMT

Hi,

what do you mean:
>>
hardcoded in array
<<

The following code - slightly modified to my prior solution - produces this output:
/usr/bin udir

#!/usr/bin/ksh
set -A filesys /var /usr/bin
typeset -i i=0
cat >test.txt </var/tmp tmpdir
/usr/local hostdir
#/var sysdir
/usr udir
/usr/bin udir
EOF

while [ $i -lt ${#filesys[@]} ]
do
position_params=$(nawk -v fsys=${filesys[$i]} 'BEGIN {pat="^"fsys"$"}
/^[ ]*#/ {next}
$1 ~ pat {print}' test.txt)
[ -n "$position_params" ] && echo $position_params
((i=i+1))
done

Now let us know, what are your exact input and output request.

mfG Peter

Re: Awk - help

Senthil Prabu.S_1 — Wed, 18 Apr 2007 05:49:45 GMT

Hello Peter,
I modified your first script to get it working..:-)Thanks a lot!!!!

And closing this thread.

Re: Awk - help

Senthil Prabu.S_1 — Wed, 18 Apr 2007 05:50:38 GMT

Got the solution, closing it.