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Full Discussion: Sed Newbie Question
Top Forums UNIX for Dummies Questions & Answers Sed Newbie Question Post 302525211 by bakunin on Thursday 26th of May 2011 04:57:25 AM
Old 05-26-2011
The basic pattern for sed substitutions is:

Code:
s[delimiter]<pattern>[delimiter]<replacement pattern>[delimiter]<options>

The delimiter is any single character, you just have to use the same throughout the command. Traditionally the slash ("/") is used, but you could use any other either. The "pattern" is what you look for, the "replacement pattern" is what you want to replace it with.

Per default only the first occurrence ina line is replaced, if you want to change every occurrence of the pattern in a line you have to add the option "g" (for "global").

As an example: change the first "a" to "b" ("aaaaa" will become "baaaa"):

Code:
s/a/b/

change every "a" to "b":

Code:
s/a/b/g

It would be easy to apply this to your problem and write as a search pattern: "[A-Za-z]:". Unfortunately things are a litle bit more complicated: we will have to "remember" in the replacement pattern which character we have matched in the search pattern. "A:" should be replaced by "A.", but "B:" by "B.", etc.

There is a device in sed which can accomplish this. It is like defining a variable and using its content in the replacement pattern: The parts in the search pattern we enclose in "\(" and "\)" are being remembered and we can use "\1" ("\2", ...) in the replacement pattern to call these.

Here is an example:

Code:
s/\([A-Za-z]\)/=\1=/g

every single character is replaced by itself, surrounded by equal signs. Input: "a b c d" Output: "=a= =b= =c= =d=".

Applying this to your problem:

Code:
s/\([A-Za-z]\):/\1./g

I hope this helps.

bakunin
 

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SVK::Log::Filter::Grep(3)				User Contributed Perl Documentation				 SVK::Log::Filter::Grep(3)

SYNOPSIS
SVK::Log::Filter::Grep - search log messages for a given pattern DESCRIPTION
The Grep filter requires a single Perl pattern (regular expression) as its argument. The pattern is then applied to the svn:log property of each revision it receives. If the pattern matches, the revision is allowed to continue down the pipeline. If the pattern fails to match, the pipeline immediately skips to the next revision. The pattern is applied with the /i modifier (case insensitivity). If you want case-sensitivity or other modifications to the behavior of your pattern, you must use the "(?imsx-imsx)" extended pattern (see "perldoc perlre" for details). For example, to search for log messages that match exactly the characters "foo" you might use svk log --filter "grep (?-i)foo" However, to search for "foo" without regards for case, one might try svk log --filter "grep foo" The result of any capturing parentheses inside the pattern are not available. If demand dictates, the Grep filter could be modified to place the captured value somewhere in the stash for other filters to access. If the pattern contains a pipe character ('|'), it must be escaped by preceding it with a '' character. Otherwise, the portion of the pattern after the pipe character is interpreted as the name of a log filter. STASH
/PROPERTY MODIFICATIONS Grep leaves all properties and the stash intact. perl v5.10.0 2008-08-04 SVK::Log::Filter::Grep(3)
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