Difference between revisions of "bash arithmetic"
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(Created page with "examples a=`expr $a + 1` a=`expr 5 + 3` category:bash") |
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| + | == using let == | ||
| + | |||
| + | let "TOTAL = ( $A + 5 ) / $b" | ||
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| + | == floating point using bc == | ||
| + | |||
| + | TOTAL=`echo "( $A + 5 ) / $b" | bc -l | ||
| + | |||
| + | '''using scale to control number of digits''' | ||
| + | |||
| + | $ echo "1 / 100" | bc -l | ||
| + | .01000000000000000000 | ||
| + | |||
| + | $ echo "scale =2; 1 / 100" | bc -l ~ | ||
| + | .01 | ||
| + | |||
| + | |||
| + | using expr | ||
a=`expr $a + 1` | a=`expr $a + 1` | ||
a=`expr 5 + 3` | a=`expr 5 + 3` | ||
| + | |||
| + | == bash built in hex 2 dec == | ||
| + | '''hex digits ab a1 48 39''' | ||
| + | |||
| + | $ echo $((0xab)) | ||
| + | 171 | ||
| + | $ echo -e $((0xab)) $((0xa1)) $((0x48)) $((0x39)) | ||
| + | 171 161 72 57 | ||
| + | |||
| + | '''hex to dotted quad IP notation''' | ||
| + | |||
| + | $ echo 'aba14839' |sed 's/../ 0x&/g' |xargs printf "%d.%d.%d.%d\n" | ||
| + | 171.161.72.57 | ||
| + | |||
| + | |||
[[category:bash]] | [[category:bash]] | ||
Latest revision as of 02:17, 2 January 2015
using let
let "TOTAL = ( $A + 5 ) / $b"
floating point using bc
TOTAL=`echo "( $A + 5 ) / $b" | bc -l
using scale to control number of digits
$ echo "1 / 100" | bc -l .01000000000000000000 $ echo "scale =2; 1 / 100" | bc -l ~ .01
using expr
a=`expr $a + 1`
a=`expr 5 + 3`
bash built in hex 2 dec
hex digits ab a1 48 39 $ echo $((0xab)) 171 $ echo -e $((0xab)) $((0xa1)) $((0x48)) $((0x39)) 171 161 72 57 hex to dotted quad IP notation $ echo 'aba14839' |sed 's/../ 0x&/g' |xargs printf "%d.%d.%d.%d\n" 171.161.72.57
