use different nonzero status values to indicate the reason why the
command failed.
.SH NOTES
-Linux is a flavor of Unix, and as a first approximation
-all user commands under Unix work precisely the same under
-Linux (and FreeBSD and lots of other Unix-like systems).
+Linux is a flavor of UNIX, and as a first approximation
+all user commands under UNIX work precisely the same under
+Linux (and FreeBSD and lots of other UNIX-like systems).
.LP
Under Linux there are GUIs (graphical user interfaces), where you
can point and click and drag, and hopefully get work done without
first reading lots of documentation.
-The traditional Unix environment
+The traditional UNIX environment
is a CLI (command line interface), where you type commands to
tell the computer what to do.
That is faster and more powerful,
.I df
will tell you how much of your disk is still free.
.SS "Processes"
-On a Unix system many user and system processes run simultaneously.
+On a UNIX system many user and system processes run simultaneously.
The one you are talking to runs in the
.IR foreground ,
the others in the