GNU Core Utilities

The GNU Core Utilities or coreutils is a package of GNU software containing implementations for many of the basic tools, such as cat, ls, and rm, which are used on Unix-like operating systems. 
In September 2002, the "GNU coreutils" were created by merging the earlier packages "textutils", "shellutils", and "fileutils", along with some other miscellaneous utilities. In July 2007, the license of the GNU coreutils was updated from GPLv2 to GPLv3.
The GNU core utilities support long options as parameters to the commands, as well as the relaxed convention allowing options even after the regular arguments (unless the environment variable is set). Note that this environment variable enables a different functionality in BSD.
See the List of GNU Core Utilities commands for a brief description of included commands.
Alternative implementation packages are available in the FOSS ecosystem, with a slightly different scope and focus, or license. For example, GPLv2-licensed BusyBox and BSD-licensed Toybox are available for use in embedded devices.