in reply to Re: Delete a line from the file
in thread Delete a line from the file

Hi, Thanks for the Help ,yes,It's output from shell. I've tried using shell_escape, as below, 
 perl -pi -e shell_escape('s#\Q(.*)\$/\',\$lines,\$matches))10.(.*)\$/
+\',\$lines,\$matches))(.*)\$/\',\$lines,\$matches))# #gi')  result.tx
+t > result1.txt

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but got the same erroe .. Unmatched '. Whether I have used the shell_escape correctly or not.. Thanks,

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Re^3: Delete a line from the file
by ikegami (Patriarch) on Jul 16, 2008 at 22:26 UTC
    \' doesn't work in single-quoted literals in bourne shell. 
    $ echo 'foo\'bar'
>                      <- waits for closing '

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    Fixes: 

    $ echo foo\'bar
foo'bar
$ echo "foo'bar"
foo'bar
$ echo 'foo'\''bar'
foo'bar
$ echo 'foo'"'"'bar'
foo'bar

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Re^3: Delete a line from the file
by NetWallah (Canon) on Jul 16, 2008 at 22:35 UTC
    From the bash manual:
    A single quote may not occur between single quotes, even when preceded by a backslash.
    Hence - my previous suggestion is invalid - there is no "escaping" inside a single-quote.

    Here is a shell trick to try: 

     '"'"'

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    Replace all perl-directed single quotes with that, and it should work.

    Extremely ugly, though. Here is how it works:
    It starts in single quotes, and which you want a single quote you come out, go into double quotation to quote a single quote, then come out of double quotation, to go back into single quotes again.

    Using this trick, your command passes the shell's syntax: 

     perl -pi -e 's#\Q(.*)\$/'"'"',\$lines,\$matches))10.(.*)\$/'"'"',\$li
+nes,\$matches))(.*)\$/'"'"',\$lines,\$matches))# #gi' result.txt > re
+sult1.txt

-- Output (from perl - bash is happy!!!) --
Can't open result.txt: No such file or directory.

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    Update: I just noticed that my shell trick is identical to ikegami's (++) last example.

         Have you been high today? I see the nuns are gay! My brother yelled to me...I love you inside Ed - Benny Lava, by Buffalax

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      Hey NetWallah Thanks for the help...The error is gone...But cant see any result in result1.txt .. So , may be some match is not done or so... the string in file to be removed is 
      (.*)$/',$lines,$matches)        10.(.*)$/',$lines,$matches)     (.*)$/
+',$lines,$matches)

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      There are tabs in between.. Thanks
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        I think you are over-escaping the shell.

        Since you are in single-quotes, attempting to escape the $ using \$ causes the $ to be interpreted literally by perl where you did not intend.

        Specifically, I think you intended perl to see "$var" , but you have a "\" preceding the $ , and that \ is passed to perl, so perl thinks you want a literal $var, instead of interpolating.

        Here is how perl currently sees your re: 

          s#\Q(.*)\$/',\$lines,\$matches))10.(.*)\$/',\$lines,\$matches))(.*)\
+$/',\$lines,\$matches))# #gi

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        You need to remove all attempts to escape all $'s in front of variable names.

        Update:The problem is that \Q interpolates and disallows \$ - see my response below.

             Have you been high today? I see the nuns are gay! My brother yelled to me...I love you inside Ed - Benny Lava, by Buffalax

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