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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 OPENSOLARIS

shells

shells(4)							   File Formats 							 shells(4)

NAME

       shells - shell database

SYNOPSIS

       /etc/shells

DESCRIPTION

       The shells file contains a list of the shells on the system. Applications use this file to determine whether a shell is valid. See getuser-
       shell(3C). For each shell a single line should be present, consisting of the shell's path, relative to root.

       A hash mark (#) indicates the beginning of a comment; subsequent characters up to the end of the line are not interpreted by  the  routines
       which search the file. Blank lines are also ignored.

       The following default shells are used by utilities: /bin/bash, /bin/csh, /bin/jsh, /bin/ksh, /bin/ksh93, /bin/pfcsh, /bin/pfksh, /bin/pfsh,
       /bin/sh, /bin/tcsh, /bin/zsh, /sbin/jsh, /sbin/sh, /usr/bin/bash, /usr/bin/csh, /usr/bin/jsh, /usr/bin/ksh, /usr/bin/ksh93, /usr/bin/pfcsh,
       /usr/bin/pfksh, /usr/bin/pfsh, and /usr/bin/sh, /usr/bin/tcsh, /usr/bin/zsh, and /usr/sfw/bin/zsh. /etc/shells overrides the default list.

       Invalid shells in /etc/shells could cause unexpected behavior, such as being unable to log in by way of ftp(1).

FILES

       /etc/shells    list of shells on system

SEE ALSO

       vipw(1B), ftpd(1M), sendmail(1M), getusershell(3C), aliases(4)

SunOS 5.11							    20 Nov 2007 							 shells(4)
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