s6-portable-utils is a set of tiny general Unix utilities, often performing well-known tasks such as cut and grep, but optimized for simplicity and small size. They were designed for embedded systems and other constrained environments, but they work everywhere.
Other set of small utilities are usually system-specific; for instance, the (otherwise excellent) BusyBox project only works on Linux.
Some of s6-portable-utils' programs are a conformant implementation of a POSIX utility as determined by the Single Unix Specification, version 4; the relevant documentation pages mentions this. However, none of the s6-portable-utils programs supports internationalization.
It is now an explicit non-goal of s6-portable-utils to duplicate the work of existing projects that aim to provide a lightweight implementation of standard commands. No more rewriting of standard commands will occur in s6-portable-utils; the package is now used to host specific utilities such as s6-uniquename.
s6-portable-utils is free software. It is available under the ISC license.
git clone git://git.skarnet.org/s6-portable-utils
All these commands exit 111 if they encounter a temporary error, and 100 if they encounter a permanent error - such as a misuse.