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Full Discussion: Maths with variables
Top Forums Shell Programming and Scripting Maths with variables Post 302388191 by TonyFullerMalv on Tuesday 19th of January 2010 04:43:33 PM
Old 01-19-2010
The bc(1) command can do scripted mathematics for you, e.g.:

Code:
$ RI=30
$ RESULT=`echo "scale=3; 10 / ${RI}" | bc`
$ echo $RESULT
.333

The above will work in BASH, Bourne and Korn shell.

So the script in Bourne would be:
Code:
RI_min=10
RI_max=30
RI_inc=1

# Run Flex2d for each RI
RI=${RI_min}
echo "Calculating flexure for:"
while [ ${RI} -le ${RI_max} ]; do
  RI=`expr ${RI} + ${RI_inc}`
  PI=`echo "scale=3; 10 / ${RI}" | bc`
  echo PI = ${PI}
done

and running this produces:
Code:
Calculating flexure for:
PI = .909
PI = .833
PI = .769
PI = .714
PI = .666
PI = .625
PI = .588
PI = .555
PI = .526
PI = .500
PI = .476
PI = .454
PI = .434
PI = .416
PI = .400
PI = .384
PI = .370
PI = .357
PI = .344
PI = .333
PI = .322

I'll leave you to translate it into tcsh if you must.

This site:
Math Commands
goes into more detail about calculations in scripts.
 

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LEARN ABOUT DEBIAN

surfraw-update-path

SURFRAW-UPDATE-PATH(1)					User Contributed Perl Documentation				    SURFRAW-UPDATE-PATH(1)

NAME

       surfraw-update-path - updates PATH in shell config files

SYNOPSIS

       surfraw-update-path [-add] [-remove] [-check] [-sys] [-all] [-help] [-shell=SHELL]

DESCRIPTION

       surfraw-update-path adds the surfraw elvi directory (/usr/lib/surfraw) to your PATH in your shell's config file.

       Currently it supports bash, sh, csh, tcsh, ash, dash, ksh, pdksh, zsh, rc, and es

       Don't forget to login again or source your login files for it to take effect.

OPTIONS

       -check
	   Checks to see if the surfraw config code is present.  This is the default.

       -add
	   Adds the surfraw config code.

       -remove
	   Removes the surfraw config code

       -sys
	   Updates the system-wide shell config instead of the user.  Must be done as root.

       -shell=SHELL
	   Selects the shell to configure. Defaults to the value of the $SHELL environment variable.

	   Currently supported shells are:

	   sh, ash, bash, dash, csh, tcsh, ksh, pdksh, zsh, rc, and es.

       -all
	   Attempts to configure the startup files for all known shells

       -help
	   Gives a usage message

RETURN VALUE

       -check returns 0 if the surfraw code is present in the file, 1 if it is not found, or 2 on error.

       All other options return 0 on success, or 2 on error.

ENVIRONMENT

       SHELL
	   Used to determine which shell to configure, if -shell is not given.

       HOME
	   Used to find users config files.

       ENV Used by posix-compliant shells to specify a startup rc file.

       ZDOTDIR
	   Used to find user config files for zsh. If not set, defaults to HOME.

SEE ALSO

       surfraw(1), sh(1), ash(1), bash(1), dash(1), csh(1), tcsh(1), ksh(1), pdksh(1), zsh(1), rc(1), es(1)

AUTHOR

       Ian Beckwith <ianb@erislabs.net>

perl v5.12.4							    2011-07-12						    SURFRAW-UPDATE-PATH(1)
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