Specific Options
The following directories, or symbolic links to directories, must be in /usr/bin, if the corresponding subsystem is installed:
/usr/bin/X11 must be a symlink to /usr/X11R6/bin if the latter exists.
The following files, or symbolic links to files, must be in /usr/bin, if the corresponding subsystem is installed:
| Command | Description |
|---|---|
| perl | The Practical Extraction and Report Language (optional) |
| python | The Python interpreted language (optional) |
| tclsh | Simple shell containing Tcl interpreter (optional) |
| wish | Simple Tcl/Tk windowing shell (optional) |
| expect | Program for interactive dialog (optional) |
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. They may be symlinks to the physical location of the shell interpreters.