topic Re: elif loop help in Operating System - Linux

elif loop help

lawrenzo_1 — Thu, 21 Jun 2007 03:19:17 GMT

Hello all,

I am trying to list files in a directory and if they are *.Z then uncompress or if they are *.gz then gunzip however the sytax I run will uncompress the *.Z files but error on the *.gz files, here is my syntax:

for COMPRESSED in `awk '{print $1}' list`
do
if [ -f *.Z ] ; then
echo "uncompressing $COMPRESSED"
uncompress $COMPRESSED
elif [ -f *.gz ] ; then
echo "uncompressing gzipped $COMPRESSED"
gunzip $COMPRESSED
else
continue
fi
done

any help would be greatly appreciated or another solution?

Please note that there thousands of files and running 2 find commands would put additional load to the server.

Thanks

Chris.

Re: elif loop help

Dennis Handly — Thu, 21 Jun 2007 03:29:54 GMT

You shouldn't be using awk. And you need pattern matching in your ifs:
for COMPRESSED in $(< list); do

if [[ $COMPRESSED = *.Z ]]; then
...
elif [[ $COMPRESSED = *.gz ]]; then
...
fi
done

Re: elif loop help

Dennis Handly — Thu, 21 Jun 2007 03:32:14 GMT

>Me: You shouldn't be using awk.

Oops, that assumes you only have filename in your file "list" and not other columns you want to ignore.

Re: elif loop help

lawrenzo_1 — Thu, 21 Jun 2007 03:40:26 GMT

Thanks Dennis,

yes the list file has 3 fields so awk would work however I will try you example with the while loop ie:

while read FILE DATE YEAR
do
if [[ FILE = *.Z ]] ; then
etc
etc
done < list

will let you know how I get on

cheers

Chris

Re: elif loop help

lawrenzo_1 — Thu, 21 Jun 2007 03:46:59 GMT

again thankyou

works a treat and picked up something new:

for files in $(etc
etc.

Chris.

Re: elif loop help

Hemmetter — Thu, 21 Jun 2007 03:49:53 GMT

Hi Chris,

if think you want to test $COMPRESSED
either [ -f $COMPRESSED ]
if $COMPRESSED is the filename including the postfix .Z (.gz)
or [ -f ${COMPRESSED}.Z ]
if $COMPRESSED does not have the .Z

rgds
HGH

Re: elif loop help

Dennis Handly — Thu, 21 Jun 2007 04:10:17 GMT

If you have lots of pattern matching, you can use a case:
for COMPRESSED in ...; do
case $COMPRESSED in
*.Z) echo "uncompressing $COMPRESSED"
;;
*.gz|*.tgz) echo "uncompressing gzipped $COMPRESSED"
;;
*) echo "not one of those guys"
;;
esac
done

I used "|" above to allow both patterns.

Re: elif loop help

lawrenzo_1 — Thu, 21 Jun 2007 05:02:40 GMT

ok nice one,

I like that as it appears to be very effiecient.

Thanks

Re: elif loop help

lawrenzo_1 — Thu, 21 Jun 2007 05:03:23 GMT