[SOLVED] weird thing is happening for -f switch

sysmicuser · 02-26-2012, 07:00 PM

Hallo Folks,

I am having issue with -f switch for conditional if statement.

export TAR_FILENAME=${CCB_ENVNAME}_PRE_${RELEASE}_UPGRADE_`hostname -s`.tar.gz

if [[ -f "${TAR_FILENAME}" ]];then
echo "Application tar ball exist please check backup directory"
exit 1
fi

this one doesn't work if file is present it should fail, but it overwrites existing file, any problemo in script?

Please assist.

Many thanks.

TKH · 02-26-2012, 07:08 PM

what is the output?
anyway, have you install perl?

chrism01 · 02-26-2012, 07:15 PM

Try this

Code:

#!/bin/bash

# this shows what script is really doing
set -xv

export TAR_FILENAME=${CCB_ENVNAME}_PRE_${RELEASE}_UPGRADE_`hostname -s`.tar.gz

if [[ -f "${TAR_FILENAME}" ]]
then
    echo "Application tar ball exist please check backup directory"
    exit 1
fi

Does filename have a space in it?

@TKH: this is shell, not Perl

sysmicuser · 02-26-2012, 07:19 PM

No file name doesnot has a space in it.
I shall try iv option alongwith -x

Shall update soon.

Cheers

sysmicuser · 02-26-2012, 07:25 PM

@TKH

as chirsm01 says it is bash and not perl

sysmicuser · 02-26-2012, 07:28 PM

@chrism01
in meanwhile can you please xplain me what is the difference and what is correct style?

{code}
if [[ -f "${TAR_FILENAME}" ]]
then
echo "Application tar ball exist please check backup directory"
exit 1
fi

{code}

OR
{code}
if [[ -f "${TAR_FILENAME}" ]];then
echo "Application tar ball exist please check backup directory"
exit 1
fi
{code}

What is the correct syntax?

chrism01 · 02-26-2012, 07:35 PM

Technically either is allowed, but I prefer mine as being easier to read, including indenting

You might find these useful
http://rute.2038bug.com/index.html.gz
http://tldp.org/LDP/Bash-Beginners-G...tml/index.html
http://www.tldp.org/LDP/abs/html/

PS code tags howto https://www.linuxquestions.org/quest...do=bbcode#code for posting on LQ

sysmicuser · 02-26-2012, 07:41 PM

My bad I was using confluence standard on forum!

Thanks for that.

Ran script twice still cannot understand why the heck it is not working

Code:

echo $TAR_FILENAME
+ echo BLD02CCA_PRE_1.9.0.6.6.12_UPGRADE_tmelbld12.tar.gz

if [[ -f "${TAR_FILENAME}" ]]
then
        echo "Application tar ball exist please check backup directory"
        exit 1
fi
+ [[ -f BLD02CCA_PRE_1.9.0.6.6.12_UPGRADE_tmelbld12.tar.gz ]]

# ***************************************************************
# *                                                             *
# *    Create Tarball file and put it in the backup directory   *
# *                                                             *
# ***************************************************************

Since the file is generated programmatically I cannot any reason the if -f should fail

sysmicuser · 02-26-2012, 07:43 PM

Would my check condition change for a .tar.gz file.

The manual says if [[ -f file ]] true for a regualr file not sure if that .tar.gz is a regular file?

sysmicuser · 02-26-2012, 07:45 PM

Code:

file BLD02CCA_PRE_1.9.0.6.6.12_UPGRADE_tmelbld12.tar.gz
PRD01CCA_PRE_1906612UPGRADE-tcolpdapp01.transurban.com.au.tar.gz: gzip compressed data, from Unix, last modified: Sun Feb 26 09:33:43 2012

Is that the case that -f switch is not working?

sysmicuser · 02-26-2012, 07:53 PM

moving slowly and steadily.

noclobber variable may give me answer

sysmicuser · 02-26-2012, 07:57 PM

still close

Code:

 set -o
allexport       off
braceexpand     on
emacs           on
errexit         off
errtrace        off
functrace       off
hashall         on
histexpand      on
history         on
ignoreeof       off
interactive-comments    on
keyword         off
monitor         on
noclobber       off
noexec          off
noglob          off
nolog           off
notify          off
nounset         off
onecmd          off
physical        off
pipefail        off
posix           off
privileged      off
verbose         off
vi              off
xtrace          off

if this one works, I would be happy as I have learnt something today !

sysmicuser · 02-26-2012, 09:40 PM

Now I am wondering what role does if [[ -f ] does if we can achieve same by set -o noclobber?

I commented out if loop and just set, set -o noclobber and it works fantatstic.

Still not satisfied why -f is not working................

catkin · 02-26-2012, 10:01 PM

Perhaps the file is not a regular file. You could test by

Code:

file "${TAR_FILENAME}"
if [[ -f "${TAR_FILENAME}" ]]
then
...

BTW, the { and } in "${TAR_FILENAME}" are not wrong but they are not required.

sysmicuser · 02-26-2012, 11:17 PM

@catkin yes the file is not regular file.
It says
gzip compressed data

how can I test then?