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Full Discussion: System call oddity
Top Forums Shell Programming and Scripting System call oddity Post 302937686 by beomagi on Saturday 7th of March 2015 07:14:37 PM
Old 03-07-2015
Code System call oddity
Hi all, I'm trying to use bash to create a basic parser for some text, because basic grep/sed/awk have all my needs covered.

So, I'm creating the chain of grep/sed I need and trying the execute that on the data I gather.

The problem is, it's not working as it does when hardcoded.


e.g.
Code:
#!/bin/sh
##a b c
##a b d
##a "b" x
##a p "b"

me=$0
data=`cat $0`
func1="grep 'a b'"
func2="grep ^##"
func3="grep ## | grep b"
echo "$data" | grep 'a b'
#echo "$data" | $func1


So, the last two lines should be the same.

using the 2nd to last line with grep 'a b'
Code:
beomagi@VBMagi ~ $ ./test.sh 
##a b c
##a b d
func1="grep 'a b'"
echo "$data" | grep 'a b'

using the variable for grep 'a b'
Code:
beomagi@VBMagi ~ $ ./test.sh 
grep: b': No such file or directory


But variables work in the case of the $func2 variable in my test script.
Code:
beomagi@VBMagi ~ $ ./test.sh 
##a b c
##a b d
##a "b" x
##a p "b"


So what's the deal? I have text in a variable, and want to filter it using a string of grep/sed/awk - but once there's any spaces or quotes in my filter's variable, it breaks.

Ideas?
 

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LEARN ABOUT LINUX

zegrep

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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