Cram
One tool to list, extract, create, test, convert and mount archives. It also signs files, builds recovery sidecars and finds duplicates across your drives.
Get Cram.
Free, with nothing held back. Every engine feature is in it, and will stay in it.
On Linux and Apple Silicon macOS, one line does it:
curl -fsSL https://raw.githubusercontent.com/lukr54/cram/main/install.sh | shThe same engine, with an interface. Free to download. Some features are reserved for Pro.
One-time payment, no subscription. The command line is unaffected.
What Cram reads and writes.
The native format stores repeated data once and repacks JPEGs losslessly.
What we claim, we measured.
Creating an archive from 2.8 GB and 42,151 files, on a 24-thread Ryzen 9 5900X. Each tool at its own default effort, median of three runs.
| Create | Archive | Memory | |
|---|---|---|---|
| Cram | 6.9 s | 1.99 GB | 2.6 GB |
| 7-Zip 26.01 | 65.5 s | 2.30 GB | 7.4 GB |
| WinRAR 7.12 | 84.1 s | 1.99 GB | 0.3 GB |
9.4× faster than 7-Zip and 12.1× faster than WinRAR, matching WinRAR’s archive size and beating 7-Zip’s by 13%. In fast mode the same archive takes 2.8 s.
The size depends on your data; the speed does not. That corpus is 15% duplicate content, which the .cram format stores once and no setting on either competitor can collapse. On corpora that never repeat themselves, Cram stays 6–11× faster than 7-Zip but writes 9–19% more.
Measured on a single machine. The corpus is downloadable and rebuilds itself identically, and the measurement script is published with it, so you can re-run the table yourself.
The limits, stated up front.
Binaries are not code-signed
Windows shows a SmartScreen warning on first run. Click "More info", then "Run anyway".
Mounting is Windows-only
Mounting an archive as a folder needs the Windows Client-ProjFS feature, which is off by default. Every other command works everywhere.
RAR is read-only
Cram reads RAR archives and will never create them. The UnRAR licence forbids building a compressor from its source.
The engine is public.
The engine and the command line are published under MIT or Apache 2.0. You can read them, build them and reuse them. Cram Studio, the graphical interface, is proprietary software distributed under its own licence agreement.
View the repositoryA question about Cram?
Common cases are answered on our support page. Otherwise write to cram-support@nexalit.fr. Command-line bugs go through GitHub.