Filesystem Hierarchy Standard

This is the primary directory of executable commands on the system.

"/usr/bin" mh X11

"Binaries that are not needed in single-user mode" Commands for the MH mail handling system Symlink to /usr/X11R6/bin

Tree 4.2.1

Because shell script interpreters (invoked with #!<path> on the first line of a shell script) cannot rely on a path, it is advantageous to standardize their locations. The Bourne shell and C-shell interpreters are already fixed in /bin, but Perl, Python, and Tcl are often found in many different places. /usr/bin/perl, /usr/bin/python, and /usr/bin/tcl should reference the perl, python, and tcl shell interpreters, respectively. They may be symlinks to the physical location of the shell interpreters.