-
Common Commands
Here is a list of helpful common commands
used in a shell telnet environment.
man topic
Display the contents of the system manual
pages (help) on the topic. Try man
man first. Press "q" to
quit the viewer. The command info topic works
similar and may contain more up-to-date
information. Manual pages can be hard to
read. Try any_command --help for
short, easy to digest help on a command.
apropos topic
Give a list of the commands that have something
to to do with my topic.
help command
Display brief info on a bash (shell) build-in
command.
ls
List the content of the current directory.
Under Linux, the command "dir"
is an alias to ls. Many users have "ls" to
be an alias to "ls --color".
ls -al |more
List the content of the current directory,
all files (also those starting with a dot),
and in a long form. Pipe the output through
the "more" command, so that the
display pauses after each screenful. hit
space bar to go down a page
cd directory
Change directory. Using "cd" without
the directory name will take you to your
home directory. "cd -" will take
you to your previous directory and is a convenient
way to toggle between two directories. "cd
.." will take you one directory up.
cp source destination
Copy files. E.g., cp /home/stan/existing_file_name
. will copy a file to my current
working directory. Use the "-r" option
(for recursive) to copy the contents of whole
directories, e.g. , cp -r my_existing/dir/
~ will copy a subdirectory under
my current working directory to my home directory.
mv source destination
Move or rename files. The same command is
used for moving and renaming files and
directories.
rm files
Remove (delete) files. You will be asked
for confirmation of deleation, if you don't
want this, use the "-f" (=force)
option, e.g., rm -f * will
remove all files in my current working
directory, no questions asked. BE CAREFUL
HERE!!
mkdir directory
Make a new directory.
rmdir directory
Remove an empty directory.
rm -r files
(recursive remove) Remove files, directories,
and their subdirectories. Careful with
this command, you can easily remove all
files on the system with such a command
executed on the top of your directory tree,
and there is no undelete in Linux (yet).
cat filename |
more
View the content of a text file called "filename",
one page a time. The "|"
is the "pipe" symbol (on many American
keyboards it shares the key with "\")
The pipe makes the output stop after each
screenful. For long files, it is sometimes
convenient to use the commands head and tail
that display just the beginning and the end
of the file. If you happened to use "cat" a
binary file and your terminal displays funny
characters afterwards, you can restore it
with the command "reset".
less filename
Scroll through a content of a text file.
Press q when done. "Less" is
roughly equivalent to "more" ,
the command you know from DOS, although
very often
"less" is more convenient than "more".
pico filename
Edit a text file using the simple and standard
text editor called pico.
pico -w filename
Edit a text file, while disabling the long
line wrap.
find / -name "filename"
Find the file called "filename" on
your filesystem starting the search from
the root directory "/". The "filename" may
contain wildcards (*,?).
locate filename
Find the file name of which contains the
string "filename". Easier and
faster than the previous command but depends
on a database that normally rebuilds at
night.
top
-
Editing Files
Using vi
Below is a very short tutorial in the most
basic use of the vi editor:
To get into a vi session:
~$ vi filename
This will open an existing file for editing
or create the file and open for editing if
it does not exist.
To get out without saving:
:q!
To get out with saving:
:wq
To delete characters, type
'x' with cursor over character [ if in INSERT
mode, press Esc then x ]. To delete group
of characters type '#x' where # is the number
of characters to be deleted.
To delete an entire line,
type 'dd' at the beginning of the line.
To delete a group of lines type '#dd' where
# is the number of lines to be deleted.
INSERT MODE:
'INSERT' will appear at bottom of screen
and remain while in insert mode.
Escape insert mode by hitting 'Esc' key.
(You must escape insert mode or any mode
in order to save and/or quit)
To insert characters after the cursor, type
'i' . To insert characters before the cursor,
type 'a'. To insert characters at the end
of the line, type 'A'
To open a line for insertion below the line
the cursor is on, type 'o'. To open a line
for insertion above the line the cursor is
on, type 'O'
To move forward a page
type 'Ctrl f', backward a page type 'Ctrl
b'. To move quickly to the bottom of the
file, type 'G'. To move quickly to the top
of a file, type '1G'.
To search, type '/search_string'.
Type 'n' to get next instance of search string.
Get a book for all the
many other things that can be done with the
'vi' editor. Alternatively or also, read
the 'man' entries for vi. At prompt, type,
'man vi'.
~$ man vi
top
-
Editing Files
Using Pico (recommended for beginners)
Using Pico is highly recommended by beginners!
It is fairly easy to use and a very good
editor.
To start, type in:
pico -w filename
-if the "filename" is a new file,
it will automatically create a new one, if
it exists, it will edit the file
To search for something in the document: "Ctrl
+ W"
To exit, "Ctrl + X" and "y" to
save your file
To Cut text out (cuts each line at a time), "Ctrl
+ K"
top
-
File Backups
using Compression/Decompression
tar -zxvf filename.tar.gz
To Untar a tarred and compressed tarball
(*.tar.gz or *.tgz) that you downloaded
from the Internet.
tar -xvf filename.tar
Untar a tarred but uncompressed tarball (*.tar).
gunzip filename.gz
Decompress a zipped file (*.gz" or *.z).
Use gzip (also zip or compress)
if you wanted to compress files to this file
format.
bunzip2 filename.bz2
(=big unzip) Decompress a file (*.bz2) zipped
with bzip2 compression utility. Used for
big files.
unzip filename.zip
Decompress a file (*.zip) zipped with a compression
utility compatible with PKZIP for DOS.
unarj e filename.arj
Extract the content of an *.arj archive.
uudecode -o outputfile filename
Decode a file encoded with uuencode. uu-encoded
files are typically used for transfer of
non-text files in e-mail (uuencode transforms
any file into an ASCII file).
top
-
Help! I cannot
connect with SSH or Secure FTP!
For those on `Lion`, you will have to change
your host to this: Lion.performancehosting.net and
make sure your port is correct.
top
