`cmp`

File-oriented gzip and zlib compression via host tools - shells out to system gzip or python3 zlib to compress or decompress files by path. For native in-process compression across multiple algorithms, see cmpz.

Load with: use cmp

What this module does

cmp provides simple file-to-file compression by delegating to external host tools. Gzip operations call the system gzip binary; zlib operations invoke a one-liner python3 -c script using Python's built-in zlib module. The high-level helper writes a string to a temporary file and then gzip-packs it to the destination, removing the temp file afterwards.

Because all operations go through shell processes, there is no in-process memory overhead for large files, but you need gzip and python3 available on PATH.

Quick example

use cmp

# Gzip-compress a file
cmpgz("input.txt", "input.txt.gz")

# Gzip-decompress
cmpgz("input.txt.gz", "input.txt")

# Zlib compress/decompress files
cmcmp("raw.bin", "raw.bin.zlib")
cmcmp("raw.bin.zlib", "raw.bin")

# Compress a string directly to a .gz file
cmpgz("Hello, world!", "hello.gz")

Functions

Gzip

cmpgz(src, dst) - compress

Runs gzip -c {src} > {dst}. Both paths are shell-quoted. Returns dst.

cmpgz(src, dst) - decompress

Runs gzip -dc {src} > {dst}. Returns dst.

cmpgz(s, dst) - string → gz

Writes string s to a temporary file (dst + ".tmp_plain"), gzip-packs it to dst, then removes the temporary file. Returns dst.

Zlib

cmcmp(src, dst) - compress

Reads src, compresses with Python's zlib.compress, writes to dst. Returns dst.

cmcmp(src, dst) - decompress

Reads src, decompresses with Python's zlib.decompress, writes to dst. Returns dst.

Notes

Requires gzip and python3 on the system PATH.
For in-process compression without external dependencies, use cmpz which supports gzip, brotli, zstd, lz4, bzip2, xz, and 7z natively.
Requires txt, fs, and os.