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.