clhasher

CLHasher is a Linux command line utility to get non-cryptographic hashes of strings or data.

clhasher <options> <algorithm flag> <input>

• Installing
• Updating
• Uninstalling
• Use
• Algorithms
• Options
• Escaping

Installing

1. Clone the repository.

# Clone into directory 'clhasher'
git clone https://github.com/penguin-teal/clhasher.git clhasher
# Enter that directory
cd clhasher
# Go to specific release (v1.1.0 is latest)
git switch --detach v1.1.0

2. Build the project.

# Make a release build
make release

3. Install. To install there is a make install target and an optional DESTDIR variable.

# Install to /usr/local/bin: (ROOT is required)
sudo make install
# or to other dir:
# make install DESTDIR=/some/other/dir

Updating

# Go to where you cloned the repository
cd clhasher
# Get the changes
git pull
# Switch to latest (v1.1.0 is latest)
git switch --detach v1.1.0
# Clean just to be safe then build release again
make clean release
# Install like you did before (ROOT is required)
sudo make install

Uninstalling

To uninstall just rm the executable file:

# if you used make install: (ROOT is required)
rm /usr/local/bin/clhasher -i
# or if you installed using DESTDIR=*:
# rm /some/other/dir/clhasher -i

Use

This creates a 64-bit hash using the FNV-1A algorithm:

clhasher --fnv1a-64 'My String'

Which prints:

9354639888599838980

You can also format the output better:

clhasher -ax --fnv1a-64 'My String'

Which prints:

u64 [0]:    0x81D25B6A69B17104

The -a option is for --annotate which produces a little more of a formatted output, and -x is for --hex which prints the hash as a base-16 hexadecimal number.

You can also split large integers into smaller ones:

clhasher -ax --fnv0-128 --split-64 'splitting'

u64 [0]:        0x2FE83015B8E8ABEC
u64 [8]:        0x12A4876D7700025E

It can also read from STDIN:

gcc --version | grep --color=never 'gcc' | clhasher -x --fnv1a-64

DBEF2942FEC1D09F

More examples:

# Hash entire file:
clhasher -x -i ./Makefile --fnv1-32
# 50C5D52

# Hash up to 20 chars from a file:
clhasher -x -i ./Makefile --fnv1a-32 -z 20
# 577B9B35

# Hash the NUL terminator:
clhasher -x0 --fnv1a-64 'TESTSTR'
# BEB7B33DE037BF70

# Use escape codes:
clhasher -xe --fnv1a-64 'line1\n\tline2'
# B2063D2905CD97E1

# Use multiline hashing:
clhasher -axm --fnv1a-64
# > Hello
# #01  u64 [0]:	0x63F0BFACF2C00F6B
# > Sir
# #02  u64 [0]:	0xF76EA5B545A72761
# > Hashed
# #03  u64 [0]:	0x6CEC30CFBB0E4C7C
# > Sir
# #04  u64 [0]:	0xF76EA5B545A72761
# > Lol
# #05  u64 [0]:	0x68344BC6E6C587E0
# > Ctrl + D
# 1 Collisions
#
# Hashes #2 (Sir) and #4 (Sir) both get this hash:
# #01  u64 [0]:	0xF76EA5B545A72761

Algorithms

Currently the following algorithms are supported:

• FNV-0: 32, 64, & 128 (--fnv0-32, --fnv0-64, --fnv0-128)
• FNV-1: 32, 64, & 128 (--fnv1-32, --fnv1-64, --fnv1-128)
• FNV-1A: 32, 64, & 128 (--fnv1a-32, --fnv1a-64, --fnv1a-128)

Options

Here are all the options. You can also run clhasher --help for a similar list.

Usage:

clhasher <options> <algorithm option> <string>

Or omit <string> for STDIN:

echo 'hello' | clhasher <options> <algorithm option>

Miscellaneous:

• -o <FILE>/--out=<FILE> Print into a file. Defaults to - for STDOUT.
• -i <FILE>/--in=<FILE> Read from a file if no value argument is given. Defaults to - for STDIN.
• -z <BYTES>/--length=<BYTES> Number of bytes of input to hash. Defaults to 0 for automatic.
• -0/--hash-nul When length is automatic, includes the \0 NUL to hash (by default does not hash the NUL).
• -e/--escape Allow escape sequences in the inputted string (see Escaping).
• -m/--multi Individually hash each line of input (splits input by a line feed). Also automatically reports any collisions.
• -v/--verbose Describe what is happening.
• -?/--help Print help list.
• --usage See usage message.
• -V/--version Print program version.

Algorithms:

• --fnv0-32 FNV-0 32-bit algorithm.
• --fnv0-64 FNV-0 64-bit algorithm.
• --fnv0-128 FNV-0 128-bit algorithm.
• --fnv1-32 FNV-1 32-bit algorithm.
• --fnv1-64 FNV-1 64-bit algorithm.
• --fnv1-128 FNV-1 128-bit algorithm.
• --fnv1a-32 FNV-1A 32-bit algorithm.
• --fnv1a-64 FNV-1A 64-bit algorithm.
• --fnv1a-128 FNV-1A 128-bit algorithm.

Output Formatting:

• -a/--annotate Print output with nicer formatting.
• --hi-to-lo When splitting the output, print the most significant part first (i.e. simulates big-endian on an integer scale).
• -x/--hex Print base-16 hexadecimal numbers.
• --octal Print base-8 octal numbers.
• --base-10 Print base-10 "normal" numbers (default).

Splitting:

• --split-32 Split hash output into one/multiple 32-bit numbers (e.g. 64-bit prints two 32-bit numbers).
• --split-64 Split hash output into one/multiple 64-bit numbers (default).

Escaping

You can enable escaping via -e. Enabling escaping means that the string must end at a NUL, and therefore having a string containing NULs like -z <SIZE> allows will not work.

Escape Code	ASCII	Description
\n	0A	New line
\r	0D	Carriage return
\t	09	Tab
\\	5C	Backslash
\0	00	Nul*
\XXX		Octal Code*
\oXXX		Octal Code*
\xXX		Hex Code*

*If a NUL character exists the string will end there.