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Use of sed inside perl

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# 1  
Old 10-16-2015
Use of sed inside perl
Code:
$string="test.binary.value";
$toggle="test.binary.value=true";
host=test.server.com

my $returnCode = system ( "ssh $host 'cp -p /tmp/testfile /tmp/testfile.bkup; sed -i 's/\$string.*/\$toggle/g' /tmp/testfile'" );

cat testfile

test.binary.value=false

Scenario: I am trying to change the value of that binary to true from false. The user provides $toggle as an argument to the perl script. I want to change the line what ever be the previous line in the file to what user entered. Its like search and replace.

The above is my code but its not working, but its simply making the file empty/null. I am not sure whats the mistake I am making. Any help would be greatly appreciated.
# 2  
Old 10-16-2015
Instead of
Code:
my $returnCode = system ( "ssh $host 'cp -p /tmp/testfile /tmp/testfile.bkup; sed -i 's/\$string.*/\$toggle/g' /tmp/testfile'" );

try
Code:
my $returnCode = qx( ssh $host "cp -p /tmp/testfile /tmp/testfile.bkup; sed -i s/$string.*/$toggle/ /tmp/testfile" );

This User Gave Thanks to Aia For This Post:
Tuxidow
# 3  
Old 10-16-2015
This is not Perl. This is 99% shell code in a transparently thin wrapping of perl. You could dispense with the Perl and hardly see a difference:

Code:
string="test.binary.value"
toggle="test.binary.value=true"
host=test.server.com

ssh "$host" "cp -p /tmp/testfile /tmp/testfile.bkup ; sed -i 's/$string.*/$toggle/g' /tmp/testfile"
returnCode="$?"

Also, perl wastes an entire shell every time you do system("something"); so if your perl code mostly resembles this, it might be better to do everything in 1 shell than 37.
Last edited by Corona688; 10-16-2015 at 12:39 PM..
This User Gave Thanks to Corona688 For This Post:
Tuxidow
# 4  
Old 10-19-2015
This is a snippet from a CGI code. I agree that I can do it in shell. But the situation is not permitting. :P
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