Bash Math - Revision history

Admin: /* Complex Math */

2012-08-13T23:21:29Z

Complex Math

← Older revision		Revision as of 23:21, 13 August 2012
Line 70:		Line 70:

	<pre>		<pre>
	$ echo "25.~~2222~~+6.~~33333~~" \| bc		$ echo "25.7 + 90.1384" \| bc

	31.~~55553~~		115.8384

	$ echo "25.7 >= 90.1384" \| bc		$ echo "25.7 >= 90.1384" \| bc
Line 79:		Line 79:
	$ echo "25.7 <= 90.1384" \| bc		$ echo "25.7 <= 90.1384" \| bc
	1		1

			$ echo "sqrt(85)" \| bc
			9

			$ echo "sqrt(85.0)" \| bc
			9.2

			$ echo "sqrt(85.000000)" \| bc
			9.219544

	</pre>		</pre>

	~~{{Stub\|section}}~~

	=Operators=		=Operators=

Admin: /* Complex Math */

2012-08-13T22:58:45Z

Complex Math

← Older revision		Revision as of 22:58, 13 August 2012
Line 62:		Line 62:

	To do anything more complex than basic integer math, you have to use the program <code>bc</code> (bash calculator).		To do anything more complex than basic integer math, you have to use the program <code>bc</code> (bash calculator).

			You can find the bc man page here: http://unixhelp.ed.ac.uk/CGI/man-cgi?bc+1

			The gist of how you script mathematical operations with bc is, you echo the operation you want to perform, and you pipe it to bc. bc then performs the calculation and spits out the result.

			For example:

			<pre>
			$ echo "25.2222+6.33333" \| bc

			31.55553

			$ echo "25.7 >= 90.1384" \| bc
			0

			$ echo "25.7 <= 90.1384" \| bc
			1
			</pre>

	{{Stub\|section}}		{{Stub\|section}}

Admin at 15:34, 28 May 2011

2011-05-28T15:34:57Z

← Older revision		Revision as of 15:34, 28 May 2011
Line 121:		Line 121:


			{{Programs}}
	~~[[Category:~~Unix]]		{{Unix Programs}}
	~~[[Category:~~Math Programs]]		{{Math Programs}}
	~~[[Category:Programs]]~~

Admin: /* Complex Math */

2011-05-28T07:16:43Z

Complex Math

← Older revision		Revision as of 07:16, 28 May 2011
Line 63:		Line 63:
	To do anything more complex than basic integer math, you have to use the program <code>bc</code> (bash calculator).		To do anything more complex than basic integer math, you have to use the program <code>bc</code> (bash calculator).

	{{~~Stump~~\|section}}		{{Stub\|section}}



	=Operators=		=Operators=

Admin at 07:16, 28 May 2011

2011-05-28T07:16:19Z

← Older revision		Revision as of 07:16, 28 May 2011
Line 56:		Line 56:
	25		25
	</source>		</source>



			=Complex Math=

			To do anything more complex than basic integer math, you have to use the program <code>bc</code> (bash calculator).

			{{Stump\|section}}



	=Operators=		=Operators=

Admin: /* =Division */

2011-05-28T07:13:01Z

=Division

← Older revision		Revision as of 07:13, 28 May 2011
Line 33:		Line 33:
	</source>		</source>

	===Division==		==Division==

	<source lang="bash">		<source lang="bash">

Admin at 07:12, 28 May 2011

2011-05-28T07:12:45Z

← Older revision		Revision as of 07:12, 28 May 2011
Line 117:		Line 117:
	[[Category:Math Programs]]		[[Category:Math Programs]]
	[[Category:Programs]]		[[Category:Programs]]
	~~[[Category:Software]]~~

Admin: Created page with "=Basic Math= Bash has some built-in functionality for really basic integer math, like addition, subtraction, multiplication, and division. ==Addition== $ ..."

2011-05-28T07:12:30Z

Created page with "=Basic Math= Bash has some built-in functionality for really basic integer math, like addition, subtraction, multiplication, and division. ==Addition== <source lang="bash"> $ ..."

New page

=Basic Math=

Bash has some built-in functionality for really basic integer math, like addition, subtraction, multiplication, and division.

==Addition==

<source lang="bash">
$ sum=$((2+2)) && echo $sum
4

$ sum=$((sum+10)) && echo $sum
14
</source>

==Subtraction==

<source lang="bash">
$ diff=$((100-50)) && echo $diff
50

$ diff=$((diff-25)) && echo $diff
25
</source>

==Multiplication==

<source lang="bash">
$ prod=$((2*8)) && echo $prod
16

$ a=9; b=3; prod=$((a*b)) && echo $prod
27
</source>

===Division==

<source lang="bash">
$ a=14; b=2; div=$((a/b)) && echo $div
7
</source>

==Remainder==

<source lang="bash">
$ a=10; b=4; z=$((a%b)) && echo $z
2
</source>

==Exponentiation==

<source lang="bash">
$ z=5 && echo $z
5

$ zz=$((z**2)) && echo $zz
25
</source>

=Operators=

You can use the increment and decrement operators <code>++</code> and <code>--</code> as follow:

'''Increment++'''

The increment operator can be used as either a prefix or postfix operator, i.e. as <code>++i</code> or <code>i++</code>. Example:

<source lang="bash">
$ z=1 && echo $z
1

$ ((++z)) && echo $z
2

$ ((++z)) && echo $z
3

$ ((++z)) && echo $z
4
</source>

This can be used in bash for loops as follows:

<source lang="bash">
for ((i=1; i <=$NUM ; i++)); do
echo $i
done
</source>

'''Decrement--'''

Like the increment operator, this can be a prefix or postfix operator, i.e. <code>--i</code> or <code>i--</code>:

<source lang="bash">
$ z=1 && echo $z
1

$ ((--z)) && echo $z

$ ((--z)) && echo $z
-1

$ ((--z)) && echo $z
-2

$ ((--z)) && echo $z
-3
</source>

Notice that <code>echo $z</code> doesn't print anything if z=0.

[[Category:Unix]]
[[Category:Math Programs]]
[[Category:Programs]]
[[Category:Software]]