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Help on the regular expresion =~

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Top Forums Shell Programming and Scripting Help on the regular expresion =~
# 1  
Old 06-14-2011
Question Help on the regular expresion =~
Code:
my $hw_plf_desc = `grep hw_platform $NODE_CFG_FILE`;
  if($hw_plf_desc =~ /Netra X4270 X4446A M2 /)

Could someone explain the use of =~ .... this works only for perl . What is the alternate for the same in shell . Could any one convert this to shell script
Last edited by pludi; 06-14-2011 at 07:13 AM..
# 2  
Old 06-14-2011
=~ is regex binding operator
More about it here.
# 3  
Old 06-14-2011
Quote:
Originally Posted by frintocf
Code:
my $hw_plf_desc = `grep hw_platform $NODE_CFG_FILE`;
  if($hw_plf_desc =~ /Netra X4270 X4446A M2 /)

Could someone explain the use of =~ .... this works only for perl . What is the alternate for the same in shell . Could any one convert this to shell script

Code:
#!/bin/bash
hw_plf_desc=$(grep hw_platform $NODE_CFG_FILE)
if [ "X$(echo $hw_plf_desc  | grep 'Netra X4270 X4446A M2')" == "X" ] ; then
   echo "Not a Nextra X4270 X4446A M2"
else 
   echo "Woohoo it's a Nextra X4270 X4446A M2"
fi

Last edited by Skrynesaver; 06-14-2011 at 07:49 AM.. Reason: missing brackets in command substitution
This User Gave Thanks to Skrynesaver For This Post:
frintocf
# 4  
Old 06-14-2011
Equivalent in shell scripting would be something like this

Code:
 
 if [$hw_plf_desc -eq [Netra X4270 X4446A M2] ]
then
...
..
fi

# 5  
Old 06-14-2011
for string comparision ...its always good to use == Smilie ....
Code:
eg:
v=haiif [ $v == "Netra X4270 X4446A M2" ];then
echo "compare hai"
else
echo "not matching"
fi
not matching

# 6  
Old 06-14-2011
e.g.
Code:
ds=`grep "Netra X4270 X4446A M2" tmpfile`
"$ds" = "[Netra X4270 X4446A M2]" ]; echo "Match"

o.p
Match
Last edited by Franklin52; 06-14-2011 at 08:06 AM.. Reason: Please use code tags, thank you
# 7  
Old 06-14-2011
Skrynesaver

It works fine .

Could you please explain the capital x ( X) does
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