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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

xzegrep

XZGREP(1)							     XZ Utils								 XZGREP(1)

NAME

       xzgrep - search compressed files for a regular expression

SYNOPSIS

       xzgrep [grep_options] [-e] pattern file...
       xzegrep ...
       xzfgrep ...
       lzgrep ...
       lzegrep ...
       lzfgrep ...

DESCRIPTION

       xzgrep  invokes	grep(1)  on  files  which may be either uncompressed or compressed with xz(1), lzma(1), gzip(1), or bzip2(1).  All options
       specified are passed directly to grep(1).

       If no file is specified, then standard input is decompressed if necessary and fed to grep(1).  When reading from  standard  input,  gzip(1)
       and bzip2(1) compressed files are not supported.

       If  xzgrep  is  invoked as xzegrep or xzfgrep then egrep(1) or fgrep(1) is used instead of grep(1).  The same applies to names lzgrep, lze-
       grep, and lzfgrep, which are provided for backward compatibility with LZMA Utils.

ENVIRONMENT

       GREP   If the GREP environment variable is set, xzgrep uses it instead of grep(1), egrep(1), or fgrep(1).

SEE ALSO

       grep(1), xz(1), gzip(1), bzip2(1), zgrep(1)

Tukaani 							    2010-09-27								 XZGREP(1)
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