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Full Discussion: Another sed Syntax Puzzle . . .
Top Forums Shell Programming and Scripting Another sed Syntax Puzzle . . . Post 302918829 by Don Cragun on Thursday 25th of September 2014 05:26:34 PM
Old 09-25-2014
Quote:
Originally Posted by LinQ
... ... ...

Apart from enormous skill, what does one look to for this type of syntax? It would be immensely helpful if there was an applet on a site somewhere to pop out the commands; but I guess the world isn't finished yet...

... ... ...
If you are serious about learning how to use Linux and UNIX system utilities, first carefully study the differences between filename pattern matching, basic regular expressions, and extended regular expressions and learn how to write patterns, BREs, and EREs to match whatever you might want to match. (Then you'll immediately know what type of expression you need to use for a particular type of string match.) Then study the man pages for the utilities you want to use. Everything you needed for this job comes from knowing BREs and from the address ranges section of the sed man page.

And, finally, practice makes perfect. Play around with various problems until the solutions to them just flow from your fingertips. Smilie Read the problems posed here; look at the suggestions provided; if they don't make sense to you, read the man pages; if they still don't make sense, ask questions!

Learn something new everyday.
This User Gave Thanks to Don Cragun For This Post:
LinQ
 

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LEARN ABOUT DEBIAN

shtool-subst

SHTOOL-SUBST.TMP(1)					      GNU Portable Shell Tool					       SHTOOL-SUBST.TMP(1)

NAME

       shtool-subst - GNU shtool sed(1) substitution operations

SYNOPSIS

       shtool subst [-v|--verbose] [-t|--trace] [-n|--nop] [-w|--warning] [-q|--quiet] [-s|--stealth] [-i|--interactive] [-b|--backup ext]
       [-e|--exec cmd] [-f|--file cmd-file] [file] [file ...]

DESCRIPTION

       This command applies one or more sed(1) substitution operations to stdin or any number of files.

OPTIONS

       The following command line options are available.

       -v, --verbose
	   Display some processing information.

       -t, --trace
	   Enable the output of the essential shell commands which are executed.

       -n, --nop
	   No operation mode. Actual execution of the essential shell commands which would be executed is suppressed.

       -w, --warning
	   Show warning on substitution operation resulting in no content change on every file. The default is to show a warning on substitution
	   operations resulted in no content change on all files.

       -q, --quiet
	   Suppress warning on substitution operation resulting in no content change.

       -s, --stealth
	   Stealth operation. Preserve timestamp on file.

       -i, --interactive
	   Enter interactive mode where the user has to approve each operation.

       -b, --backup ext
	   Preserve backup of original file using file name extension ext.  Default is to overwrite the original file.

       -e, --exec cmd
	   Specify sed(1) command directly.

       -f, --file cmd-file
	   Read sed(1) command from file.

EXAMPLE

	#   shell script
	shtool subst -i -e 's;(c) ([0-9]*)-2000;(c) 1-2001;' *.[ch]

	#    RPM spec-file
	%install
	    shtool subst -v -n 
		-e 's;^(prefix=).*;1 $RPM_BUILD_ROOT%{_prefix};g' 
		-e 's;^(sysconfdir=).*;1 $RPM_BUILD_ROOT%{_prefix}/etc;g' 
		`find . -name Makefile -print`
	    make install

HISTORY

       The GNU shtool subst command was originally written by Ralf S.  Engelschall <rse@engelschall.com> in 2001 for GNU shtool.  It was prompted
       by the need to have a uniform and convenient patching frontend to sed(1) operations in the OpenPKG package specifications.

SEE ALSO

       shtool(1), sed(1).

18-Jul-2008							   shtool 2.0.8 					       SHTOOL-SUBST.TMP(1)
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