P

PATH
A colon-separated list of directories that are searched when the shell looks for commands and .'d files. An empty string resulting from a leading or trailing colon, or two adjacent colons is treated as a ., the current directory.

For more information, see ksh in the Utilities Reference.

PATH_MAX
The maximum permitted length of a pathname.
POSIX_STRICT
If this environment variable is set, some utilities (e.g., cp, ls, and more) interpret options according to POSIX specifications.
POSIXLY_CORRECT
This environment variable is used by Unix-style operating systems to alter behavior to comply with POSIX where it's different from the OS's default behavior. POSIXLY_CORRECT is a de facto standard that isn't defined by POSIX.

Here are some of its effects:

  • If the POSIXLY_CORRECT environment variable is set, functions that check the length of a pathname do so before removing any redundant . and .. components. If POSIXLY_CORRECT isn't set, the functions check the length after removing any redundant components.
  • If the POSIXLY_CORRECT environment variable is set, the posix option to be enabled for ksh. For more information, see POSIX mode in the documentation for ksh.
PROCESSOR
Specifies the target CPU when building an image filesystem. If not set, the default is the same as the CPU of the host system (e.g., x86). For more information, see mkifs in the Utilities Reference.