Shell Programming and Scripting

Hi community,

i am processing some output with awk:

cat initHC2.sap | awk '{ print $0 ~ /^tape_addr*/? gsub(/[",","(",")"]/," ") $1" "$2" ("$4","$3")" : ""}'| sort | tail -2

with gsub, i replace in two lines

tape_address = (/dev/nrmt0h,/dev/nrmt1h)
tape_address_rew = (/dev/rmt0h,/dev/rmt1h)

this : "(" ")" "," with a whitespace to get fields

tape_address = /dev/nrmt0h /dev/nrmt1h
tape_address_rew = /dev/rmt0h /dev/rmt1h

and then i am able to flip the tapes with the fields

it works good, but there is ONE BIG PROBLEM:
The return code given by awk, printed at the beginning of the line!

result is allways this line:

3tape_address = (/dev/nrmt1h,/dev/nrmt0h)
3tape_address_rew = (/dev/rmt1h,/dev/rmt0h)

i need to get rid of the numbers, does anyone know how to do this? i need to turn of awk's return code somehow...

Another problem is how do i manage awk to give no line out if the statement is false?

$0 ~ <pattern>? <then> : <else> }'

I don't want no <else> or if i need to give an else value, what should i write there to get no line printed at all? even "" prints a single line and i hav a lot of annoying empty lines at the end...

regards,markus

hello there everybody...? does nobody have an idea ..?

-regards, markus

try redirect the error code to dev null

# your_commands 2> /dev/null

hi
i think the problem is with print try removing print statement awk will print by default
and the return value is from gsub

Code:

gsub(regex, str [, target]) N 

Globally substitute str for each match of the regular expression regex in the string target. If target is not supplied, defaults to $0. Return the number of substitutions.

bye

Hi there,

removing the print statement caused that awk did not print anything at all, redirection of error code did not succeed either. any other ideas left?

-regards,markus

You could try resetting the Field Seperator, e.g...

Code:

$ cat initHC2.sap
tape_address = (/dev/nrmt0h,/dev/nrmt1h)
tape_address_rew = (/dev/rmt0h,/dev/rmt1h)

$ awk -F '[(,)]' '{printf "%s(%s,%s)\n", $1, $3, $2}' initHC2.sap
tape_address = (/dev/nrmt1h,/dev/nrmt0h)
tape_address_rew = (/dev/rmt1h,/dev/rmt0h)

Hi Ygor,

your command did not work correctly, because somehow, awk put a (,) after each line of the output:

[...]
# NT: "mt -f $ rewind"(,)
rewind = "mt -f $ rew"(,)
(,)
# rewind and set offline command(,)
[...]

however, you have shown me the right way. after some modification, it worked:

awk -F '[,)(]' '{print $0 ~ /^tape_addr*/ ? $1"("$3","$2")\n" : $0}' initHC2.sap | grep ^tape_addr

tape_address = (/dev/nrmt1h,/dev/nrmt0h)
tape_address_rew = (/dev/rmt1h,/dev/rmt0h)

Tanks a lot!