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How to compare that file name is empty?

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# 1  
Old 12-06-2009
How to compare that file name is empty?
i am finding some pattern this way..

fname=`grep -w "^$index" $HOME/UnixCw/backup/Path.txt`

how to check that fname is empty i.e. if pattren doesnt found then i want to do other operations....
Last edited by AbhijitIT; 12-06-2009 at 03:22 PM..
# 2  
Old 12-06-2009
look at the -s file test operator
# 3  
Old 12-06-2009
I tried but its not working...can you please elaborate more..I am very new to unix...sorry for trouble
# 4  
Old 12-06-2009
Code:
if [ -z $fname ]
then
    # do something
fi

Read the man page for test.
# 5  
Old 12-06-2009
ignore my post about -s. I misunderstood what you were trying to do. there is no need to have a $fname variable if your just testing for a match.

Code:
if grep -q -w "^$index" $HOME/UnixCw/backup/Path.txt
then
   #do something
fi

# 6  
Old 12-07-2009
if [ -z $variable ]

This will check whether the $variable is Null.
# 7  
Old 12-07-2009
Quote:
Originally Posted by frank_rizzo
ignore my post about -s. I misunderstood what you were trying to do. there is no need to have a $fname variable if your just testing for a match.

Code:
if grep -q -w "^$index" $HOME/UnixCw/backup/Path.txt
then
   #do something
fi

You could also do:

Code:
grep -q -w "^$index" $HOME/UnixCw/backup/Path.txt

if [ ! $? = "0" ]
then
    #dowhatever
fi

If your grep finds the string the exit status will be 0 and you can branch based upon that, or the reverse.
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