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Full Discussion: Math operator in Variable
Top Forums Shell Programming and Scripting Math operator in Variable Post 302954850 by samcompda on Friday 11th of September 2015 01:55:10 PM
Old 09-11-2015
Math operator in Variable

I wanted to write a bash script which take a variable X with math operator as (* or / or + or - or % and more ....). Instead of writing logic for each condition can we have a generic logic. Like sudo code below.
Code:
A=10, B=20
P = $A $X $B;
echo $P;

-------------
when X has value "*" echo $P, should return 200.
when X has value "/" echo $P, should return .5
etc ....

Last edited by vbe; 09-11-2015 at 03:52 PM.. Reason: code tags
 

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echo(1) 						      General Commands Manual							   echo(1)

NAME
echo - echo (print) arguments SYNOPSIS
[arg] ... DESCRIPTION
writes its arguments separated by blanks and terminated by a new-line on the standard output. It also understands C-like escape conven- tions; beware of conflicts with the shell's use of write an alert character backspace print line without appending a new-line form-feed new-line carriage return tab vertical tab backslash the 8-bit character whose ASCII code is the 1-, 2-, 3- or 4-digit octal number n, whose first character must be a zero. write an 8-bit value that is the zero-, one-, two- or three-digit octal number num is useful for producing diagnostics in command files and for sending known data into a pipe. Notes Berkeley differs from this implementation. The former does not implement the backslash escapes. However, the semantics of the escape can be obtained by using the option. The echo command implemented as a built-in function of follows the Berkeley semantics (see csh(1)). EXTERNAL INFLUENCES
Environment Variables determines the interpretation of arg as single and/or multi-byte characters. If is not specified in the environment or is set to the empty string, the value of is used as a default for each unspecified or empty vari- able. If is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of If any internationalization variable contains an invalid setting, behaves as if all internationalization variables are set to "C". See environ(5). International Code Set Support Single- and multi-byte character code sets are supported. AUTHOR
was developed by OSF and HP. SEE ALSO
sh(1). BUGS
No characters are printed after the first This is not normally a problem. STANDARDS CONFORMANCE
echo(1)
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