1 .\" Copyright (c) 2002 Andries Brouwer <aeb@cwi.nl>
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25 .\" 2007-10-23 mtk Added intro paragraph about section, plus a paragraph
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28 .TH INTRO 1 2007-11-15 "Linux" "Linux User's Manual"
30 intro \- introduction to user commands
32 Section 1 of the manual describes user commands and tools,
33 for example, file manipulation tools, shells, compilers,
34 web browsers, file and image viewers and editors, and so on.
36 All commands yield a status value on termination.
37 This value can be tested (e.g., in most shells the variable
39 contains the status of the last executed command)
40 to see whether the command completed successfully.
41 A zero exit status is conventionally used to indicate success,
42 and a nonzero status means that the command was unsuccessful.
43 (Details of the exit status can be found in
45 A nonzero exit status can be in the range 1 to 255, and some commands
46 use different nonzero status values to indicate the reason why the
49 Linux is a flavor of UNIX, and as a first approximation
50 all user commands under UNIX work precisely the same under
51 Linux (and FreeBSD and lots of other UNIX-like systems).
53 Under Linux, there are GUIs (graphical user interfaces), where you
54 can point and click and drag, and hopefully get work done without
55 first reading lots of documentation.
56 The traditional UNIX environment
57 is a CLI (command line interface), where you type commands to
58 tell the computer what to do.
59 That is faster and more powerful,
60 but requires finding out what the commands are.
61 Below a bare minimum, to get started.
63 In order to start working, you probably first have to open a session by
64 giving, your username and password.
69 (command interpreter) for you.
70 In case of a graphical login, you get a screen with menus or icons
71 and a mouse click will start a shell in a window.
75 One types commands to the
77 the command interpreter.
78 It is not built-in, but is just a program
79 and you can change your shell.
80 Everybody has her own favorite one.
81 The standard one is called
92 A session might go like:
96 .RB "knuth login: " aeb
97 .RB "Password: " ********
99 Tue Aug 6 23:50:44 CEST 2002
113 drwxrwxr\-x 2 aeb 1024 Aug 6 23:51 bin
114 \-rw\-rw\-r\-\- 1 aeb 37 Aug 6 23:52 tel
118 .RB "$ " "cp tel tel2"
121 drwxr\-xr\-x 2 aeb 1024 Aug 6 23:51 bin
122 \-rw\-r\-\-r\-\- 1 aeb 37 Aug 6 23:52 tel
123 \-rw\-r\-\-r\-\- 1 aeb 37 Aug 6 23:53 tel2
124 .RB "$ " "mv tel tel1"
127 drwxr\-xr\-x 2 aeb 1024 Aug 6 23:51 bin
128 \-rw\-r\-\-r\-\- 1 aeb 37 Aug 6 23:52 tel1
129 \-rw\-r\-\-r\-\- 1 aeb 37 Aug 6 23:53 tel2
130 .RB "$ " "diff tel1 tel2"
132 .RB "$ " "grep maja tel2"
138 Here typing Control-D ended the session.
142 here was the command prompt\(emit is the shell's way of indicating
143 that it is ready for the next command.
144 The prompt can be customized
145 in lots of ways, and one might include stuff like username,
146 machine name, current directory, time, and so on.
147 An assignment PS1="What next, master? "
148 would change the prompt as indicated.
150 We see that there are commands
152 (that gives date and time), and
154 (that gives a calendar).
158 lists the contents of the current directory\(emit tells you what
162 option it gives a long listing,
163 that includes the owner and size and date of the file, and the
164 permissions people have for reading and/or changing the file.
165 For example, the file "tel" here is 37 bytes long, owned by aeb
166 and the owner can read and write it, others can only read it.
167 Owner and permissions can be changed by the commands
174 will show the contents of a file.
175 (The name is from "concatenate and print": all files given as
176 parameters are concatenated and sent to "standard output"
180 the terminal screen.)
184 (from "copy") will copy a file.
188 (from "move"), on the other hand, only renames it.
192 lists the differences between two files.
193 Here there was no output because there were no differences.
197 (from "remove") deletes the file, and be careful! it is gone.
198 No wastepaper basket or anything.
203 (from "g/re/p") finds occurrences of a string in one or more files.
204 Here it finds Maja's telephone number.
205 .SS Pathnames and the current directory
206 Files live in a large tree, the file hierarchy.
209 describing the path from the root of the tree (which is called
212 For example, such a full pathname might be
214 Always using full pathnames would be inconvenient, and the name
215 of a file in the current directory may be abbreviated by giving
216 only the last component.
222 when the current directory is
227 prints the current directory.
231 changes the current directory.
239 usage: "cd", "cd .", "cd ..", "cd /" and "cd ~".
243 makes a new directory.
247 removes a directory if it is empty, and complains otherwise.
251 (with a rather baroque syntax) will find files with given name
253 For example, "find . \-name tel" would find
256 starting in the present directory (which is called
258 And "find / \-name tel" would do the same, but starting at the root
260 Large searches on a multi-GB disk will be time-consuming,
261 and it may be better to use
263 .SS Disks and filesystems
266 will attach the filesystem found on some disk (or floppy, or CDROM or so)
267 to the big filesystem hierarchy.
273 will tell you how much of your disk is still free.
275 On a UNIX system many user and system processes run simultaneously.
276 The one you are talking to runs in the
282 will show you which processes are active and what numbers these
286 allows you to get rid of them.
287 Without option this is a friendly
288 request: please go away.
289 And "kill \-9" followed by the number
290 of the process is an immediate kill.
291 Foreground processes can often be killed by typing Control-C.
292 .SS Getting information
293 There are thousands of commands, each with many options.
294 Traditionally commands are documented on
296 (like this one), so that the command "man kill" will document
297 the use of the command "kill" (and "man man" document the command "man").
300 sends the text through some
304 Hit the space bar to get the next page, hit q to quit.
306 In documentation it is customary to refer to man pages
307 by giving the name and section number, as in
309 Man pages are terse, and allow you to find quickly some forgotten
311 For newcomers an introductory text with more examples
312 and explanations is useful.
314 A lot of GNU/FSF software is provided with info files.
316 for an introduction on the use of the program
319 Special topics are often treated in HOWTOs.
321 .I /usr/share/doc/howto/en
322 and use a browser if you find HTML files there.
324 .\" Actual examples? Separate section for each of cat, cp, ...?
325 .\" gzip, bzip2, tar, rpm
projects / thirdparty / man-pages.git / blob