Convert hexadecimal to decimal numbers on the command line with the free Swiss File Knife for Windows, Mac OS X and Linux.

sfk hex value1 [value2] [...]
sfk dec value1 [value2] [...]
sfk ... +dec [+hex] -digits=n

convert numbers between decimal and hexadecimal.
largest convertable number is ((2 << 64) - 1).

options
   -digits=n  format output numbers with n digits

web reference
   http://stahlworks.com/sfk-hex

examples
   sfk hex 1048576 98765 234567
      convert 3 decimal numbers.

   sfk filt csv.txt -ssep "\t" -form "$col3" +hex
      convert 3rd column from csv.txt to hex.