bswap - Linux
Overview
bswap is a command-line utility used to swap the bytes in a value or file, effectively changing the endianness. It finds use in various scenarios, such as:
- Converting between big-endian and little-endian systems
- Reversing the order of bytes for network communication
- Manipulating binary data formats
Syntax
bswap [options] [value]
bswap [options] -f <file>
Options/Flags
- -h, –help: Display usage information
- -v, –version: Show version information
- -f, –file
: Perform byte swapping on the specified file instead of a value - -i, –inplace: Modify the file in-place instead of creating a copy
- -s, –size
: Swap bytes in blocks of the specified size (default: 4)
Examples
Simple byte swapping:
$ bswap 0x12345678
0x78563412
Swapping bytes in a file:
$ bswap -f data.bin
Swapping bytes in a file with a specific block size:
$ bswap -f data.bin -s 8
Common Issues
- Endianness mismatch: If the input value or file is not in the expected endianness, the output will be incorrect.
- File permissions: You must have write permissions to modify files in-place.
Integration
Convert a big-endian integer to little-endian:
$ printf "%08x" `bswap $(printf '%08x' 0x12345678)`
0x78563412
Reverse the order of bytes in a binary file:
$ bswap -f image.bin
Related Commands
- set: Set the value of a variable
- printf: Print formatted output
- hexdump: Dump memory in hexadecimal format