cpass

A command-line password generator written in C. Uses getrandom(2) for cryptographically secure randomness.

Building

make        # production build (-O2)
make dev    # debug build (-g -O0)

Requires GCC and a Linux system (uses getrandom syscall).

Installation

sudo make install            # installs to /usr/local/bin
make install PREFIX=~/.local # installs to ~/.local/bin
sudo make uninstall          # removes installed binary

Usage

cpass [options]

Running with no arguments outputs a bare 16-character password to stdout (suitable for piping). Use -v / --verbose for decorated output with warnings and info messages.

Options

Flag	Description
-l <length>	Set password length (default: 16)
-e <flags>	Exclude character sets (see below)
-s	Save generated password to pass.txt
-r	Delete pass.txt
-v / --verbose	Verbose output (decorated password, warnings, info messages)
-h	Show help

Exclusion flags (-e)

Combine any of the following letters after -e:

Flag	Effect
u	Exclude uppercase A-Z
l	Exclude lowercase a-z
n	Exclude numbers 0-9
s	Exclude special characters

Examples

# Default 16-character password
cpass

# 32-character password
cpass -l 32

# No special characters, no uppercase
cpass -e su

# 24-character password, numbers only
cpass -l 24 -e uls

# Save to pass.txt
cpass -s

# Pipe the password to clipboard (default bare output)
cpass | xclip -selection clipboard

# Verbose output with decorations and warnings
cpass -v -l 8

# Reset saved passwords
cpass -r

Notes

• Passwords shorter than 12 characters trigger a safety warning.
• pass.txt is append-only — -s never overwrites existing entries.
• All character sets must not be simultaneously excluded.