Some more Unix commands

1.Basic UNIX commands

ls — lists your files
ls -l — lists your files in ‘long format’, which contains lots of useful information, e.g. the exact size of the file, who owns the file and who has the right to look at it, and when it was last modified.
ls -a — lists all files, including the ones whose filenames begin in a dot, which you do not always want to see.
There are many more options, for example to list files by size, by date, recursively etc.

3.more filename — shows the first part of a file, just as much as will fit on one screen. Just hit the space bar to see more or q to quit. You can use /pattern to search for a pattern.

4.emacs filename — is an editor that lets you create and edit a file. See the emacs page. filename1 filename2 — moves a file (i.e. gives it a different name, or moves it into a different directory (see below)

6.cp filename1 filename2 — copies a file

7.rm filename — removes a file. It is wise to use the option rm -i, which will ask you for confirmation before actually deleting anything. You can make this your default by making an alias in your .cshrc file.

8.diff filename1 filename2 — compares files, and shows where they differ

9.wc filename — tells you how many lines, words, and characters there are in a file

10.chmod options filename — lets you change the read, write, and execute permissions on your files. The default is that only you can look at them and change them, but you may sometimes want to change these permissions. For example, chmod o+r filename will make the file readable for everyone, and chmod o-r filename will make it unreadable for others again. Note that for someone to be able to actually look at the file the directories it is in need to be at least executable. See help protection for more details.

11.File Compression
12.gzip filename — compresses files, so that they take up much less space. Usually text files compress to about half their original size, but it depends very much on the size of the file and the nature of the contents. There are other tools for this purpose, too (e.g. compress), but gzip usually gives the highest compression rate. Gzip produces files with the ending ‘.gz’ appended to the original filename.

13.gunzip filename — uncompresses files compressed by gzip.

14.gzcat filename — lets you look at a gzipped file without actually having to gunzip it (same as gunzip -c). You can even print it directly, using gzcat filename | lpr
16.lpr filename — print. Use the -P option to specify the printer name if you want to use a printer other than your default printer. For example, if you want to print double-sided, use ‘lpr -Pvalkyr-d’, or if you’re at CSLI, you may want to use ‘lpr -Pcord115-d’. See ‘help printers’ for more information about printers and their locations.
17.lpq — check out the printer queue, e.g. to get the number needed for removal, or to see how many other files will be printed before yours will come out
18.lprm jobnumber — remove something from the printer queue. You can find the job number by using lpq. Theoretically you also have to specify a printer name, but this isn’t necessary as long as you use your default printer in the department.
19.genscript — converts plain text files into postscript for printing, and gives you some options for formatting. Consider making an alias like alias ecop ‘genscript -2 -r \!* | lpr -h -Pvalkyr’ to print two pages on one piece of paper.
20.dvips filename — print .dvi files (i.e. files produced by LaTeX). You can use dviselect to print only selected pages. See the LaTeX page for more information about how to save paper when printing drafts.

22.Directories, like folders on a Macintosh, are used to group files together in a hierarchical structure.
23.mkdir dirname — make a new directory dirname — change directory. You basically ‘go’ to another directory, and you will see the files in that directory when you do ‘ls’. You always start out in your ‘home directory’, and you can get back there by typing ‘cd’ without arguments. ‘cd ..’ will get you one level up from your current position. You don’t have to walk along step by step – you can make big leaps or avoid walking around by specifying pathnames.
25.pwd — tells you where you currently are.
26.Finding things
27.ff — find files anywhere on the system. This can be extremely useful if you’ve forgotten in which directory you put a file, but do remember the name. In fact, if you use ff -p you don’t even need the full name, just the beginning. This can also be useful for finding other things on the system, e.g. documentation.
28.grep string filename(s) — looks for the string in the files. This can be useful a lot of purposes, e.g. finding the right file among many, figuring out which is the right version of something, and even doing serious corpus work. grep comes in several varieties (grep, egrep, and fgrep) and has a lot of very flexible options. Check out the man pages if this sounds good to you.
29.About other people
30.w — tells you who’s logged in, and what they’re doing. Especially useful: the ‘idle’ part. This allows you to see whether they’re actually sitting there typing away at their keyboards right at the moment.
31.who — tells you who’s logged on, and where they’re coming from. Useful if you’re looking for someone who’s actually physically in the same building as you, or in some other particular location.
32.finger username — gives you lots of information about that user, e.g. when they last read their mail and whether they’re logged in. Often people put other practical information, such as phone numbers and addresses, in a file called .plan. This information is also displayed by ‘finger’.
33.last -1 username — tells you when the user last logged on and off and from where. Without any options, last will give you a list of everyone’s logins. username — lets you have a (typed) conversation with another user
35.write username — lets you exchange one-line messages with another user
36.elm — lets you send e-mail messages to people around the world (and, of course, read them). It’s not the only mailer you can use, but the one we recommend. See the elm page, and find out about the departmental mailing lists (which you can also find in /user/linguistics/helpfile).
37.About your (electronic) self
38.whoami — returns your username. Sounds useless, but isn’t. You may need to find out who it is who forgot to log out somewhere, and make sure *you* have logged out.
39.finger & .plan files
of course you can finger yourself, too. That can be useful e.g. as a quick check whether you got new mail. Try to create a useful .plan file soon. Look at other people’s .plan files for ideas. The file needs to be readable for everyone in order to be visible through ‘finger’. Do ‘chmod a+r .plan’ if necessary. You should realize that this information is accessible from anywhere in the world, not just to other people on turing.
40.passwd — lets you change your password, which you should do regularly (at least once a year). See the LRB guide and/or look at help password. -u yourusername — lists your processes. Contains lots of information about them, including the process ID, which you need if you have to kill a process. Normally, when you have been kicked out of a dialin session or have otherwise managed to get yourself disconnected abruptly, this list will contain the processes you need to kill. Those may include the shell (tcsh or whatever you’re using), and anything you were running, for example emacs or elm. Be careful not to kill your current shell – the one with the number closer to the one of the ps command you’re currently running. But if it happens, don’t panic. Just try again :) If you’re using an X-display you may have to kill some X processes before you can start them again. These will show only when you use ps -efl, because they’re root processes.
42.kill PID — kills (ends) the processes with the ID you gave. This works only for your own processes, of course. Get the ID by using ps. If the process doesn’t ‘die’ properly, use the option -9. But attempt without that option first, because it doesn’t give the process a chance to finish possibly important business before dying. You may need to kill processes for example if your modem connection was interrupted and you didn’t get logged out properly, which sometimes happens.
43.quota -v — show what your disk quota is (i.e. how much space you have to store files), how much you’re actually using, and in case you’ve exceeded your quota (which you’ll be given an automatic warning about by the system) how much time you have left to sort them out (by deleting or gzipping some, or moving them to your own computer).
44.du filename — shows the disk usage of the files and directories in filename (without argument the current directory is used). du -s gives only a total.
45.last yourusername — lists your last logins. Can be a useful memory aid for when you were where, how long you’ve been working for, and keeping track of your phonebill if you’re making a non-local phonecall for dialling in.
46.Connecting to the outside world
47.nn — allows you to read news. It will first let you read the news local to turing, and then the remote news. If you want to read only the local or remote news, you can use nnl or nnr, respectively. To learn more about nn type nn, then \tty{:man}, then \tty{=.*}, then \tty{Z}, then hit the space bar to step through the manual. Or look at the man page. Or check out the hypertext nn FAQ – probably the easiest and most fun way to go.
48.rlogin hostname — lets you connect to a remote host
49.telnet hostname — also lets you connect to a remote host. Use rlogin whenever possible.
50.ftp hostname — lets you download files from a remote host which is set up as an ftp-server. This is a common method for exchanging academic papers and drafts. If you need to make a paper of yours available in this way, you can (temporarily) put a copy in /user/ftp/pub/TMP. For more permanent solutions, ask Emma. The most important commands within ftp are get for getting files from the remote machine, and put for putting them there (mget and mput let you specify more than one file at once). Sounds straightforward, but be sure not to confuse the two, especially when your physical location doesn’t correspond to the direction of the ftp connection you’re making. ftp just overwrites files with the same filename. If you’re transferring anything other than ASCII text, use binary mode.
51.lynx — lets you browse the web from an ordinary terminal. Of course you can see only the text, not the pictures. You can type any URL as an argument to the G command. When you’re doing this from any Stanford host you can leave out the part of the URL when connecting to Stanford URLs. Type H at any time to learn more about lynx, and Q to exit.

52.Miscellaneous tools
53.webster word — looks up the word in an electronic version of Webster’s dictionary and returns the definition(s) — shows the current date and time. — shows a calendar of the current month. Use e.g., ‘cal 10 1995’ to get that for October 95, or ‘cal 1995’ to get the whole year.
56.You can find out more about these commands by looking up their manpages:
man commandname — shows you the manual page for the command

•jobs — lists your currently active jobs (those that you put in the background) and their job numbers. Useful to determine which one you want to foreground if you have lots of them.
•bg — background a job after suspending it.
•fg %jobnumber — foreground a job
•!! — repeat the previous command (but CTRL-p, is safer, because you have hit return in addition)
•!pattern — repeat the last command that starts with pattern
•echo $VARIABLE — shows the value of an environment variable
•setenv — lets you set environment variables. For example, if you typed a wrong value for the TERM variable when logging in, you don’t have to log out and start over, but you can just do setenv TERM vt100 (or whatever). To see what all your environment variables are set to, type env. The one that you’re most likely to have to set is the DISPLAY variable, when using an X-display.
•unset VAR — lets you un-set environment variables. Useful, for example, if you’ve usually set autologout but want to stay logged on for a while without typing for some reason, or if you set the DISPLAY variable automatically but want to avoid opening windows for some reason.
•source filename — you need to source your dotfiles after making changes for them to take effect (or log off and in again)
•load — will show you the load average graphically
•ispell filename — will check the spelling in your file. If you’re running it on a LaTeX file use the -T option to tell it to ignore the LaTeX commands. You can create and use your own dictionary to avoid having it tell you that your own name, those of fellow linguists, and linguistics terminology are a typos in every paper you write.
•weblint — checks the syntax of html files
•latex2html — translates LaTeX files into HTML
•wn word option — lets you access the WordNet database and display, for example, synonyms, hypernyms, or hyponyms, depending on the option you select

Command editing in the tcsh
•These things are the same as in emacs:
Backspace — delete previous character
CTRL-d — delete next character
CTRL-k — delete rest of line
CTRL-a — go to start of line
CTRL-e — go to end of line
CTRL-b — go backwards without deleting
CTRL-f — go forward without deleting
•Other useful things
TAB — complete filename or command up to the point of uniqueness
CTRL-u — cancel whole line
CTRL-p — show the last command typed, then the one before that, etc.
(you can also use the cursor up key for this)
CTRL-n — go forwards in the history of commands
(you can also use the cursor down key for this)
CTRL-c — cancel the processes after it has started
CTRL-z — suspend a running process (e.g. in order to do something else in between)
you can then put the process in the background with bg
CTRL-l — redraws the screen
| (piping) — Lets you execute any number of commands in a sequence.
The second command will be executed once the first is done, and so forth, using the previous command’s output as input. You can achieve the same effect by putting the output in a file and giving the filename as an argument to the second command, but that would be much more complicated, and you’d have to remember to remove all the junkfiles afterwards. Some examples that show the usefulness of this:
ls | more — will show you one screenful at a time, which is useful with any command that will produce a lot of output, e.g. also ps -aux
man ls | grep time — checks whether the man page for ls has something to say about listing files by time – very useful when you have a suspicion some command may be capable of doing what you want, but you aren’t sure.
ls -lR | grep dvi — will show you all your dvi files – useful to solve disk space problems, since they’re large and usually can be deleted.

Unix Command Summary
See the Unix tutorial for a leisurely, self-paced introduction on how to use the commands listed below. For more documentation on a command, consult a good book, or use the man pages. For example, for more information on grep, use the command man grep.
57. Contents
• cat — for creating and displaying short files
• chmod — change permissions
• cd — change directory
• cp — for copying files
• date — display date
• echo — echo argument
• ftp — connect to a remote machine to download or upload files
• grep — search file
• head — display first part of file
• ls — see what files you have
• lpr — standard print command (see also print )
• more — use to read files
• mkdir — create directory
• mv — for moving and renaming files
• ncftp — especially good for downloading files via anonymous ftp.
• print — custom print command (see also lpr )
• pwd — find out what directory you are in
• rm — remove a file
• rmdir — remove directory
• rsh — remote shell
• setenv — set an environment variable
• sort — sort file
• tail — display last part of file
• tar — create an archive, add or extract files
• telnet — log in to another machine
• wc — count characters, words, lines
1.1.1 cat
This is one of the most flexible Unix commands. We can use to create, view and concatenate files. For our first example we create a three-item English-Spanish dictionary in a file called “dict.”
% cat >dict
red rojo
green verde
blue azul

stands for “hold the control key down, then tap ‘d'”. The symbol > tells the computer that what is typed is to be put into the file dict. To view a file we use cat in a different way:
% cat dict
red rojo
green verde
blue azul
If we wish to add text to an existing file we do this:
% cat >>dict
white blanco
black negro

Now suppose that we have another file tmp that looks like this:
% cat tmp
cat gato
dog perro
Then we can join dict and tmp like this:
% cat dict tmp >dict2
We could check the number of lines in the new file like this:
% wc -l dict2
The command wc counts things — the number of characters, words, and line in a file.
1.1.2 chmod
This command is used to change the permissions of a file or directory. For example to make a file essay.001 readable by everyone, we do this:
% chmod a+r essay.001
To make a file, e.g., a shell script mycommand executable, we do this
% chmod +x mycommand
Now we can run mycommand as a command.
To check the permissions of a file, use ls -l . For more information on chmod, use man chmod.
1.1.3 cd
Use cd to change directory. Use pwd to see what directory you are in.
% cd english
% pwd
% /u/ma/jeremy/english
% ls
novel poems
% cd novel
% pwd
% /u/ma/jeremy/english/novel
% ls
ch1 ch2 ch3 journal scrapbook
% cd ..
% pwd
% /u/ma/jeremy/english
% cd poems
% cd
% /u/ma/jeremy
Jeremy began in his home directory, then went to his english subdirectory. He listed this directory using ls , found that it contained two entries, both of which happen to be diretories. He cd’d to the diretory novel, and found that he had gotten only as far as chapter 3 in his writing. Then he used cd .. to jump back one level. If had wanted to jump back one level, then go to poems he could have said cd ../poems. Finally he used cd with no argument to jump back to his home directory.
1.1.4 cp
Use cp to copy files or directories.
% cp foo foo.2
This makes a copy of the file foo.
% cp ~/poems/jabber .
This copies the file jabber in the directory poems to the current directory. The symbol “.” stands for the current directory. The symbol “~” stands for the home directory.
1.1.5 date
Use this command to check the date and time.
% date
Fri Jan 6 08:52:42 MST 1995
1.1.6 echo
The echo command echoes its arguments. Here are some examples:
% echo this
% echo $EDITOR
% echo $PRINTER
Things like PRINTER are so-called environment variables. This one stores the name of the default printer — the one that print jobs will go to unless you take some action to change things. The dollar sign before an environment variable is needed to get the value in the variable. Try the following to verify this:
% echo PRINTER
1.1.7 ftp
Use ftp to connect to a remote machine, then upload or download files. See also: ncftp
Example 1: We’ll connect to the machine, then change director to mystuff, then download the file homework11:
% ftp solitude
Connected to
220 FTP server (Version wu-2.4(11) Mon Apr 18 17:26:33 MDT 1994) ready.
Name (solitude:carlson): jeremy
331 Password required for jeremy.
230 User jeremy logged in.
ftp> cd mystuff
250 CWD command successful.
ftp> get homework11
ftp> quit
Example 2: We’ll connect to the machine, then change director to mystuff, then upload the file collected-letters:
% ftp solitude
Connected to
220 FTP server (Version wu-2.4(11) Mon Apr 18 17:26:33 MDT 1994) ready.
Name (solitude:carlson): jeremy
331 Password required for jeremy.
230 User jeremy logged in.
ftp> cd mystuff
250 CWD command successful.
ftp> put collected-letters
ftp> quit
The ftp program sends files in ascii (text) format unless you specify binary mode:
ftp> binary
ftp> put foo
ftp> ascii
ftp> get bar
The file foo was transferred in binary mode, the file bar was transferred in ascii mode.
1.1.8 grep
Use this command to search for information in a file or files. For example, suppose that we have a file dict whose contents are
red rojo
green verde
blue azul
white blanco
black negro
Then we can look up items in our file like this;
% grep red dict
red rojo
% grep blanco dict
white blanco
% grep brown dict
Notice that no output was returned by grep brown. This is because “brown” is not in our dictionary file.
Grep can also be combined with other commands. For example, if one had a file of phone numbers named “ph”, one entry per line, then the following command would give an alphabetical list of all persons whose name contains the string “Fred”.
% grep Fred ph | sort
Alpha, Fred: 333-6565
Beta, Freddie: 656-0099
Frederickson, Molly: 444-0981
Gamma, Fred-George: 111-7676
Zeta, Frederick: 431-0987
The symbol “|” is called “pipe.” It pipes the output of the grep command into the input of the sort command.
For more information on grep, consult
% man grep
1.1.9 head
Use this command to look at the head of a file. For example,
% head essay.001
displays the first 10 lines of the file essay.001 To see a specific number of lines, do this:
% head -20 essay.001
This displays the first 20 lines of the file.
1.1.10 ls
Use ls to see what files you have. Your files are kept in something called a directory.
% ls
foo letter2
foobar letter3
letter1 maple-assignment1
Note that you have six files. There are some useful variants of the ls command:
% ls l*
letter1 letter2 letter3
Note what happened: all the files whose name begins with “l” are listed. The asterisk (*) is the ” wildcard” character. It matches any string.
1.1.11 lpr
This is the standard Unix command for printing a file. It stands for the ancient “line printer.” See
% man lpr
for information on how it works. See print for information on our local intelligent print command.
1.1.12 mkdir
Use this command to create a directory.
% mkdir essays
To get “into” this directory, do
% cd essays
To see what files are in essays, do this:
% ls
There shouldn’t be any files there yet, since you just made it. To create files, see cat or emacs.
1.1.13 more
More is a command used to read text files. For example, we could do this:
% more poems
The effect of this to let you read the file “poems “. It probably will not fit in one screen, so you need to know how to “turn pages”. Here are the basic commands:
• q — quit more
• spacebar — read next page
• return key — read next line
• b — go back one page
For still more information, use the command man more.
1.1.14 mv
Use this command to change the name of file and directories.
% mv foo foobar
The file that was named foo is now named foobar
1.1.15 ncftp
Use ncftp for anonymous ftp — that means you don’t have to have a password.
% ncftp
Connected to
> get jokes.txt
The file jokes.txt is downloaded from the machine
1.1.16 print
This is a moderately intelligent print command.
% print foo
% print
% print manuscript.dvi
In each case print does the right thing, regardless of whether the file is a text file (like foo ), a postcript file (like, or a dvi file (like manuscript.dvi. In these examples the file is printed on the default printer. To see what this is, do
% print
and read the message displayed. To print on a specific printer, do this:
% print foo jwb321
% print jwb321
% print manuscript.dvi jwb321
To change the default printer, do this:
% setenv PRINTER jwb321
1.1.17 pwd
Use this command to find out what directory you are working in.
% pwd
% cd homework
% pwd
% ls
assign-1 assign-2 assign-3
% cd
% pwd
Jeremy began by working in his “home” directory. Then he cd ‘d into his homework subdirectory. Cd means ” change directory”. He used pwd to check to make sure he was in the right place, then used ls to see if all his homework files were there. (They were). Then he cd’d back to his home directory.
1.1.18 rm
Use rm to remove files from your directory.
% rm foo
remove foo? y
% rm letter*
remove letter1? y
remove letter2? y
remove letter3? n
The first command removed a single file. The second command was intended to remove all files beginning with the string “letter.” However, our user (Jeremy?) decided not to remove letter3.
1.1.19 rmdir
Use this command to remove a directory. For example, to remove a directory called “essays”, do this:
% rmdir essays
A directory must be empty before it can be removed. To empty a directory, use rm.
1.1.20 rsh
Use this command if you want to work on a computer different from the one you are currently working on. One reason to do this is that the remote machine might be faster. For example, the command
% rsh solitude
connects you to the machine solitude. This is one of our public workstations and is fairly fast.
See also: telnet
1.1.21 setenv
% echo $PRINTER
% setenv PRINTER myprinter
% echo $PRINTER
1.1.22 sort
Use this commmand to sort a file. For example, suppose we have a file dict with contents
red rojo
green verde
blue azul
white blanco
black negro
Then we can do this:
% sort dict
black negro
blue azul
green verde
red rojo
white blanco
Here the output of sort went to the screen. To store the output in file we do this:
% sort dict >dict.sorted
You can check the contents of the file dict.sorted using cat , more , or emacs .
1.1.23 tail
Use this command to look at the tail of a file. For example,
% head essay.001
displays the last 10 lines of the file essay.001 To see a specific number of lines, do this:
% head -20 essay.001
This displays the last 20 lines of the file.
1.1.24 tar
Use create compressed archives of directories and files, and also to extract directories and files from an archive. Example:
% tar -tvzf foo.tar.gz
displays the file names in the compressed archive foo.tar.gz while
% tar -xvzf foo.tar.gz
extracts the files.
1.1.25 telnet
Use this command to log in to another machine from the machine you are currently working on. For example, to log in to the machine “solitude”, do this:
% telnet solitude
See also: rsh.
1.1.26 wc
Use this command to count the number of characters, words, and lines in a file. Suppose, for example, that we have a file dict with contents
red rojo
green verde
blue azul
white blanco
black negro
Then we can do this
% wc dict
5 10 56 tmp
This shows that dict has 5 lines, 10 words, and 56 characters.
The word count command has several options, as illustrated below:
% wc -l dict
5 tmp
% wc -w dict
10 tmp
% wc -c dict
56 tmp

ls …………….. show directory, in alphabetical order
logout …………. logs off system
mkdir ………….. make a directory
rmdir ………….. remove directory (rm -r to delete folders with files)
rm …………….. remove files
cd …………….. change current directory
man (command) …… shows help on a specific command
talk (user) …….. pages user for chat – (user) is a email address
write (user) ……. write a user on the local system (control-c to end)

pico (filename) …. easy to use text editor to edit files
pine …………… easy to use mailer
more (file) …….. views a file, pausing every screenful

sz …………….. send a file (to you) using zmodem
rz …………….. recieve a file (to the unix system) using zmodem

telnet (host) …… connect to another Internet site
ftp (host) ……… connects to a FTP site
archie (filename) .. search the Archie database for a file on a FTP site
irc ……………. connect to Internet Relay Chat
lynx …………… a textual World Wide Web browser
gopher …………. a Gopher database browser
tin, trn ……….. read Usenet newsgroups

passwd …………. change your password
chfn …………… change your “Real Name” as seen on finger
chsh …………… change the shell you log into

grep …………… search for a string in a file
tail …………… show the last few lines of a file
who ……………. shows who is logged into the local system
w ……………… shows who is logged on and what they’re doing
finger (emailaddr).. shows more information about a user
df …………….. shows disk space available on the system
du …………….. shows how much disk space is being used up by folders
chmod ………….. changes permissions on a file
bc …………….. a simple calculator

make …………… compiles source code
gcc (file.c) ……. compiles C source into a file named ‘a.out’

gzip …………… best compression for UNIX files
zip ……………. zip for IBM files
tar ……………. combines multiple files into one or vice-versa
lharc, lzh, lha …. un-arc’ers, may not be on your system

dos2unix (file) (new) – strips CR’s out of dos text files
unix2dos (file) (new) – adds CR’s to unix text files


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