Bash shell Decimal to Binary base 2 conversion
Convert decimal to binary with bash builtin commands (range 0 to 255):
D2B=({0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1})echo ${D2B[7]}00000111
echo ${D2B[85]}01010101
echo ${D2B[127]}01111111
To remove leading zeros, e.g. from ${D2B[7]}:
echo $((10#${D2B[7]}))111
This creates an array with 00000000 00000001 00000010 ... 11111101 11111110 11111111 with bash‘s brace expansion. The position in array D2B represents its decimal value.
See also: Understanding code ({0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1})
Decimal to binary conversion in Bash:
I'm using Ubuntu 14.04 to do this.
Convert the decimals 1 through 5 to binary.
el@apollo:~$ bc <<< "obase=2;1"1el@apollo:~$ bc <<< "obase=2;2"10el@apollo:~$ bc <<< "obase=2;3"11el@apollo:~$ bc <<< "obase=2;4"100el@apollo:~$ bc <<< "obase=2;5"101Bonus example:
el@apollo:~$ bc <<< "obase=2;1024"10000000000el@apollo:~$ bc <<< "obase=2;2^128"100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000