OSTYPE A name identifying the current operating system. For Fedora Linux, the OSTYPE value
is either linux or linux-gnu, depending on the type of shell you are using. (Bash
can run on other operating systems as well.)
PATH The colon-separated list of directories used to find commands that you type. The
default value for regular users is /bin:/usr/bin:/usr/local/bin:/usr/
bin/X11:/usr/X11R6/bin:~/bin. You need to type the full path or a relative
path to a command you want to run that is not in your PATH.
For the root user, the value also includes /sbin, /usr/sbin, and
/usr/local/sbin.
PPID The process ID of the command that started the current shell (for example, its parent
process).
PROMPT_COMMAND Can be set to a command name that is run each time before your shell prompt is
displayed. Setting PROMPT_COMMAND=date lists the current date/time before the
prompt appears.
PS1 Sets the value of your shell prompt. There are many items that you can read into your
prompt (date, time, username, hostname, and so on). Sometimes a command requires
additional prompts, which you can set with the variables PS2, PS3, and so on.
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Running Commands from the Shell 2
TABLE 2-7 (continued)
Variable Description
PWD This is the directory that is assigned as your current directory.
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