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Top Forums Shell Programming and Scripting Using sed with variables (again!) Post 302236739 by era on Tuesday 16th of September 2008 08:43:47 AM
Old 09-16-2008
You need to do the arithmetic separately, sed doesn't know how to subtract. awk does know; do you get an error message or does it just not do what you want? Maybe you need mawk/nawk/gawk/XPG4 awk if your default awk is a really old "traditional" awk.

Code:
foldernum=`wc -l <File_In.txt`  # note use of redirection
limit=`expr $foldernum - 3`
sed -e "$limit",'$d' File_In.txt >File_Out.txt

 

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textutil::trim(3tcl)				    Text and string utilities, macro processing 			      textutil::trim(3tcl)

__________________________________________________________________________________________________________________________________________________

NAME
textutil::trim - Procedures to trim strings SYNOPSIS
package require Tcl 8.2 package require textutil::trim ?0.7? ::textutil::trim::trim string ?regexp? ::textutil::trim::trimleft string ?regexp? ::textutil::trim::trimright string ?regexp? ::textutil::trim::trimPrefix string prefix ::textutil::trim::trimEmptyHeading string _________________________________________________________________ DESCRIPTION
The package textutil::trim provides commands that trim strings using arbitrary regular expressions. The complete set of procedures is described below. ::textutil::trim::trim string ?regexp? Remove in string any leading and trailing substring according to the regular expression regexp and return the result as a new string. This is done for all lines in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \t]+". ::textutil::trim::trimleft string ?regexp? Remove in string any leading substring according to the regular expression regexp and return the result as a new string. This apply on any line in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \t]+". ::textutil::trim::trimright string ?regexp? Remove in string any trailing substring according to the regular expression regexp and return the result as a new string. This apply on any line in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \t]+". ::textutil::trim::trimPrefix string prefix Removes the prefix from the beginning of string and returns the result. The string is left unchanged if it doesn't have prefix at its beginning. ::textutil::trim::trimEmptyHeading string Looks for empty lines (including lines consisting of only whitespace) at the beginning of the string and removes it. The modified string is returned as the result of the command. BUGS, IDEAS, FEEDBACK This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category textutil of the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have for either package and/or documentation. SEE ALSO
regexp(3tcl), split(3tcl), string(3tcl) KEYWORDS
prefix, regular expression, string, trimming CATEGORY
Text processing textutil 0.7 textutil::trim(3tcl)
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