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Full Discussion: Using sed with variables (again!)
Top Forums Shell Programming and Scripting Using sed with variables (again!) Post 302236740 by Mr_Plow on Tuesday 16th of September 2008 08:51:15 AM
Old 09-16-2008
Quote:
Originally Posted by era
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

For the awk command I didn't get an error message but it didn't do what I wanted.

However, I've played around with the code you provided and I got it to work accordingly.

Thanks.
 

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LEARN ABOUT LINUX

shtool-path

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

NAME

       shtool-path - GNU shtool command dealing with shell path variables

SYNOPSIS

       shtool path [-s|--suppress] [-r|--reverse] [-d|--dirname] [-b|--basename] [-m|--magic] [-p|--path path] str [str ...]

DESCRIPTION

       This command deals with shell $PATH variables. It can find a program through one or more filenames given by one or more str arguments.  It
       prints the absolute filesystem path to the program displayed on "stdout" plus an exit code of 0 if it was really found.

OPTIONS

       The following command line options are available.

       -s, --suppress
	   Supress output. Useful to only test whether a program exists with the help of the return code.

       -r, --reverse
	   Transform a forward path to a subdirectory into a reverse path.

       -d, --dirname
	   Output the directory name of str.

       -b, --basename
	   Output the base name of str.

       -m, --magic
	   Enable advanced magic search for ""perl"" and ""cpp"".

       -p, --path path
	   Search in path. Default is to search in $PATH.

EXAMPLE

	#   shell script
	awk=`shtool path -p "${PATH}:." gawk nawk awk`
	perl=`shtool path -m perl`
	cpp=`shtool path -m cpp`
	revpath=`shtool path -r path/to/subdir`

HISTORY

       The GNU shtool path command was originally written by Ralf S.  Engelschall <rse@engelschall.com> in 1998 for Apache. It was later taken
       over into GNU shtool.

SEE ALSO

       shtool(1), which(1).

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