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
+.PP
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 command interpreter.
It is not built-in, but is just a program
and you can change your shell.
-Everybody has her own favorite one.
+Everybody has their own favorite one.
The standard one is called
.IR sh .
See also
.BR dash (1),
.BR ksh (1),
.BR zsh (1).
-.LP
+.PP
A session might go like:
-.LP
-.RS
-.nf
+.PP
+.in +4n
+.EX
.RB "knuth login: " aeb
.RB "Password: " ********
.RB "$ " date
.RB "$ " "grep maja tel2"
maja 0501\-1136285
$
-.fi
-.RE
-.LP
+.EE
+.in
+.PP
Here typing Control-D ended the session.
-.LP
+.PP
The
.B $
here was the command prompt\(emit is the shell's way of indicating
machine name, current directory, time, and so on.
An assignment PS1="What next, master? "
would change the prompt as indicated.
-.LP
+.PP
We see that there are commands
.I date
(that gives date and time), and
.I cal
(that gives a calendar).
-.LP
+.PP
The command
.I ls
lists the contents of the current directory\(emit tells you what
.I chown
and
.IR chmod .
-.LP
+.PP
The command
.I cat
will show the contents of a file.
.BR stdout (3)),
here
the terminal screen.)
-.LP
+.PP
The command
.I cp
(from "copy") will copy a file.
-.LP
+.PP
The command
.I mv
(from "move"), on the other hand, only renames it.
-.LP
+.PP
The command
.I diff
lists the differences between two files.
Here there was no output because there were no differences.
-.LP
+.PP
The command
.I rm
(from "remove") deletes the file, and be careful! it is gone.
No wastepaper basket or anything.
Deleted means lost.
-.LP
+.PP
The command
.I grep
(from "g/re/p") finds occurrences of a string in one or more files.
.I tel
when the current directory is
.IR /home/aeb .
-.LP
+.PP
The command
.I pwd
prints the current directory.
-.LP
+.PP
The command
.I cd
changes the current directory.
-.LP
+.PP
Try alternatively
.I cd
and
The command
.I mkdir
makes a new directory.
-.LP
+.PP
The command
.I rmdir
removes a directory if it is empty, and complains otherwise.
-.LP
+.PP
The command
.I find
(with a rather baroque syntax) will find files with given name
usually
.IR less .
Hit the space bar to get the next page, hit q to quit.
-.LP
+.PP
In documentation it is customary to refer to man pages
by giving the name and section number, as in
.BR man (1).
detail.
For newcomers an introductory text with more examples
and explanations is useful.
-.LP
+.PP
A lot of GNU/FSF software is provided with info files.
Type "info info"
for an introduction on the use of the program
.IR info .
-.LP
+.PP
Special topics are often treated in HOWTOs.
Look in
.I /usr/share/doc/howto/en