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Help on any Unix command.
RTFM!
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| man {command}
| Type man ls to read the manual for
the ls command.
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| man {command} > {filename}
| Redirect help to a file to download.
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| whatis {command}
| Give short description of command. (Not on
RAIN?)
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| apropos {keyword}
| Search for all Unix commands that match keyword,
eg apropos file. (Not on RAIN?)
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List a directory
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| ls {path}
| It's ok to combine attributes, eg ls -laF
gets a long listing of all files with types.
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| ls {path_1} {path_2}
| List both {path_1} and {path_2}.
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| ls -l {path}
| Long listing, with date, size and permisions.
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| ls -a {path}
| Show all files, including important .dot files
that don't otherwise show.
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| ls -F {path}
| Show type of each file. "/" = directory,
"*" = executable.
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| ls -R {path}
| Recursive listing, with all subdirs.
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| ls {path} > {filename}
| Redirect directory to a file.
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| ls {path} | more
| Show listing one screen at a time.
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| dir {path}
| Useful alias for DOS people, or use with ncftp.
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Change to directory
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| cd {dirname}
| There must be a space between.
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| cd ~
| Go back to home directory, useful if you're
lost.
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| cd ..
| Go back one directory.
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| cdup
| Useful alias, like "cd ..", or use with ncftp.
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Make a new directory
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| mkdir {dirname}
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Remove a directory
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| rmdir {dirname}
| Only works if {dirname} is empty.
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| rm -r {dirname}
| Remove all files and subdirs. Careful!
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Print working directory
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| pwd
| Show where you are as full path. Useful if
you're lost or exploring.
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Copy a file or directory
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| cp {file1} {file2}
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| cp -r {dir1} {dir2}
| Recursive, copy directory and all subdirs.
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| cat {newfile} >> {oldfile}
| Append newfile to end of oldfile.
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Move (or rename) a
file
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| mv {oldfile} {newfile}
| Moving a file and renaming it are the same
thing.
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| mv {oldname} {newname}
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Delete a file
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| rm {filespec}
| ? and * wildcards work like
DOS should. "?" is any character; "*" is any
string of characters.
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| ls {filespec}
rm {filespec}
| Good strategy: first list a group to make
sure it's what's you think...
...then delete it all at once.
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| Download with zmodem
| (Use sx with xmodem.)
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| sz [-a|b] {filename}
| -a = ascii, -b = binary. Use
binary for everything. (It's the default?)
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| sz *.zip
| Handy after downloading with FTP. Go talk
to your spouse while it does it's stuff.
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| Upload with zmodem
| (Use rx with xmodem.)
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| rz [-a|b] (filename}
| Give rz command in Unix, THEN start
upload at home. Works fine with multiple files.
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View a text file
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| more {filename}
| View file one screen at a time.
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| less {filename}
| Like more, with extra features.
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| cat {filename}
| View file, but it scrolls.
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| cat {filename} | more
| View file one screen at a time.
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| page {filename}
| Very handy with ncftp.
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| pico {filename}
| Use text editor and don't save.
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Edit a text file.
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| pico {filename}
| The same editor PINE uses, so you already
know it. vi and emacs are also
available.
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Create a text file.
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| cat > {filename}
| Enter your text (multiple lines with enter
are ok) and press control-d to save.
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| pico {filename}
| Create some text and save it.
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Compare two files
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| diff {file1} {file2}
| Show the differences.
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| sdiff {file1} {file2}
| Show files side by side.
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Other text commands
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| grep '{pattern}' {file}
| Find regular expression in file.
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| sort {file1} > {file2}
| Sort file1 and save as file2.
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| sort -o {file} {file}
| Replace file with sorted version.
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| spell {file}
| Display misspelled words.
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| wc {file}
| Count words in file.
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Find files on system
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| find {filespec}
| Works with wildcards. Handy for snooping.
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| find {filespec} > {filename}
| Redirect find list to file. Can be big!
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Make an Alias
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| alias {name} '{command}'
| Put the command in 'single quotes'. More useful
in your .cshrc file.
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Wildcards and Shortcuts
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| *
| Match any string of characters, eg page*
gets page1, page10, and page.txt.
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| ?
| Match any single character, eg page?
gets page1 and page2, but not page10.
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| [...]
| Match any characters in a range, eg page[1-3]
gets page1, page2, and page3.
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| ~
| Short for your home directory, eg cd ~
will take you home, and rm -r ~ will
destroy it.
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| .
| The current directory.
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| ..
| One directory up the tree, eg ls ...
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| Pipes and Redirection
| (You pipe a command to another command,
and redirect it to a file.)
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| {command} > {file}
| Redirect output to a file, eg ls > list.txt
writes directory to file.
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| {command} >> {file}
| Append output to an existing file, eg cat
update >> archive adds update to end
of archive.
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| {command} < {file}
| Get input from a file, eg sort < file.txt
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| {command} < {file1} > {file2}
| Get input from file1, and write to
file2, eg sort < old.txt >
new.txt sorts old.txt and saves as new.txt.
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| {command} | {command}
| Pipe one command to another, eg ls | more
gets directory and sends it to more to
show it one page at a time.
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Permissions, important
and tricky!
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| Unix permissions concern who can
read a file or directory, write
to it, and execute it. Permissions are
granted or withheld with a magic 3-digit number.
The three digits correspond to the owner
(you); the group (?); and the world
(everyone else).
Think of each digit as a sum:
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execute permission |
= 1
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write permission |
= 2
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write and execute (1+2) |
= 3
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read permission |
= 4
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read and execute (4+1) |
= 5
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read and write (4+2) |
= 6
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read, write and execute (4+2+1) |
= 7
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| Add the number value of the permissions
you want to grant each group to make a three
digit number, one digit each for the owner,
the group, and the world. Here are some useful
combinations. Try to figure them out!
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| chmod 600 {filespec}
| You can read and write; the world can't. Good
for files.
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| chmod 700 {filespec}
| You can read, write, and execute; the world
can't. Good for scripts.
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| chmod 644 {filespec}
| You can read and write; the world can only
read. Good for web pages.
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| chmod 755 {filespec}
| You can read, write, and execute; the world
can read and execute. Good for programs you
want to share, and your public_html
directory.
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Permissions, another
way
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| You can also change file permissions
with letters:
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u = user (yourself) |
g = group |
a = everyone
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r = read |
w = write |
x = execute
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| chmod u+rw {filespec}
| Give yourself read and write permission
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| chmod u+x {filespec}
| Give yourself execute permission.
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| chmod a+rw {filespec}
| Give read and write permission to everyone.
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Applications I use
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| finger {userid}
| Find out what someone's up to.
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| gopher
| Gopher.
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| irc
| IRC, but not available on RAIN.
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| lynx
| Text-based Web browser, fast and lean.
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| ncftp
| Better FTP.
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| pico {filename}
| Easy text editor, but limited. vi and
emacs are available.
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| pine
| Email.
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| telnet {host}
| Start Telnet session to another host.
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| tin
| Usenet.
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| uudecode {filename}
uuencode {filename}
| Do it on the server to reduce download size
about 1/3.
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| ytalk {userid}
| Chat with someone else online, eg ytalk
mkummel. Please use w first so you
don't interrupt a big download!
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System info
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| date
| Show date and time.
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| df
| Check system disk capacity.
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| du
| Check your disk usage and show bytes in each
directory.
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| more /etc/motd
| Read message of the day, "motd" is a useful
alias..
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| printenv
| Show all environmental variables (in C-shell%
- use set in Korn shell$).
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| quota -v
| Check your total disk use.
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| uptime
| Find out system load.
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| w
| Who's online and what are they doing?
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