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Full Discussion: awk search pattern with special characters passed from CL
Top Forums Shell Programming and Scripting awk search pattern with special characters passed from CL Post 302397542 by alister on Monday 22nd of February 2010 01:18:09 PM
Old 02-22-2010
Quote:
Originally Posted by anbu23
If the input has quotes the
Code:
echo '/tmp/tmp"121/' | awk -v x='/tmp/tmp"' ' $0 ~ x '

In that case, the value of x inside AWK is vulnerable to regular expression metacharacters. Say, for example, that you wanted to match a pathname that had a dot. The dot would not be treated literally, but would be a wildcard matching any character. In the following example, it yields a false positive.

Code:
$ echo '/tmp/tmpnext' | awk -v x='/tmp/tmp.ext' ' $0 ~ x '
/tmp/tmpnext

There's simply no way around it. Unless you are absolutely certain that there will be no metacharacters involved, you cannot pass a value through SED or AWK's regular expression parsers (or AWK's string parser) without passing that value through some sort of sanitizing step to properly escape those special characters (which would be something of a nightmare if it had to be made safe to pass through AWK's string parsing before arriving at the regular expressioin parsing stage).

Alister

---------- Post updated at 01:18 PM ---------- Previous update was at 01:15 PM ----------

cue:

Now that i think about it, by far the simplest solution to this is fgrep. I became fixated on AWK and sed since they were listed in the original post. Unless I missed something, the following should work just fine and is not susceptible to metacharacter interference.

Code:
fgrep "$1" "$2" > dupelistfilter.txt
fgrep -v "$1" "$2" >> deletelisttest.txt

This User Gave Thanks to alister For This Post:
cue
 

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LEARN ABOUT DEBIAN

i-ls

i-ls(1) 						      General Commands Manual							   i-ls(1)

NAME

       i-ls - display file stat and checksum information for files

SYNOPSIS

       i-ls [-s] filename

       i-ls [-s] dirname

       Specify a filename for i-ls to examine, or specify a directory with dirname to examine all the files in the directory.

       -s

	      Do not show/calculate checksums for all regular files.

DESCRIPTION

       The integrit system detects intrusion by detecting when trusted files have been altered.

       integrit records information about files in a database.	i-ls allows the user to see that information for live files.

       The output syntax is the same as that of integrit.

EXAMPLES

	    i-ls /tmp/foo.txt

       shows file stat attributes for the file, "/tmp/foo.txt".

	    i-ls /tmp

       shows file stat attributes for all files in the directory, "/tmp".

	    i-ls -s /tmp

       shows file stat attributes for all files in the directory, "/tmp", also including also checksums for all regular files.

AUTHOR

       Ed L Cashin <ecashin@users.sourceforge.net>

       See the integrit web site for up to date releases and information at

	   http://integrit.sourceforge.net/

SEE ALSO

       Integrit File Verification System Manual (info), lstat(2)

Version 4.1							   Jul 27, 2001 							   i-ls(1)
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