coreutils: Multi-call invocation

 
 2.14 ‘coreutils’: Multi-call program
 ====================================
 
 The ‘coreutils’ command invokes an individual utility, either implicitly
 selected by the last component of the name used to invoke ‘coreutils’,
 or explicitly with the ‘--coreutils-prog’ option.  Synopsis:
 
      coreutils --coreutils-prog=PROGRAM ...
 
    The ‘coreutils’ command is not installed by default, so portable
 scripts should not rely on its existence.