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Full Discussion: use backtick inside awk
Top Forums Shell Programming and Scripting use backtick inside awk Post 302546988 by agama on Friday 12th of August 2011 07:45:38 PM
Old 08-12-2011
Code:
system("grep XYZ $i")

This will have issues because the $i is in quotes and thus awk will put a literal $i in the command rather than what is in column (field) i.


Code:
 system(grep XYZ $i)

This will also have issues because awk will attempt to use 'grep,' and 'XYZ' as variable names -- they probably aren't assigned and thus evaluate to blanks. The contents of field i will be put in as the command, so who knows what will actually be executed (lets hope the second field doesn't contain rm *).


What you want is a combination:
Code:
system( "grep XYZ " $i );

Notice the space after the Z. If you don't put it there you'll likely get an error from grep, or other odd results.


I still am not convinced that your grep command is correct as I don't get the feeling that $(i) contains a filename to search. Maybe it does, but it seems unlikely from what you've posted. As birei suggested, post a sample of your XML and there's a good chance that you'll not need system() at all.
Last edited by agama; 08-12-2011 at 08:46 PM.. Reason: typo
 

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LEARN ABOUT PLAN9

zgrep

ZGREP(1)						      General Commands Manual							  ZGREP(1)

NAME

       zgrep - search possibly compressed files for a regular expression

SYNOPSIS

       zgrep [ grep_options ] [ -e ] pattern filename...

DESCRIPTION

       Zgrep  invokes  grep  on  compressed  or  gzipped  files.   These  grep	options  will  cause  zgrep  to  terminate  with  an  error  code:
       (-[drRzZ]|--di*|--exc*|--inc*|--rec*|--nu*).  All other options specified are passed directly to grep.  If no file is specified,  then  the
       standard input is decompressed if necessary and fed to grep.  Otherwise the given files are uncompressed if necessary and fed to grep.

       If the GREP environment variable is set, zgrep uses it as the grep program to be invoked.

EXIT CODE

       2 - An option that is not supported was specified.

AUTHOR

       Charles Levert (charles@comm.polymtl.ca)

SEE ALSO

       grep(1), gzexe(1), gzip(1), zdiff(1), zforce(1), zmore(1), znew(1)

																	  ZGREP(1)
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