Basic Unix Commands (required forVirtual Web Server Management)

Nov '11
23

Basic Unix Commands (required forVirtual Web Server Management)

Posted by on November 23 2011 | 0 Comments
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1. Plain file manipulation

a) mv
b) cp
c) rm

2. Directory manipulation

a) pwd
b) mkdir
c) cd
d) rmdir

3. Account management

a) ln (redirecting file access)
b) passwd (changing your password)
c) zip/unzip
d) du (disk usage)

1. Plain file manipulation

a) mv

mv fred wilma

This moves fred to a file named wilma. This is the Unix way of renaming a file. mv fred flintstones/fred

This moves fred to a file named fred in the subdirectory flintstones. This example could have been written mv fred flintstones/ as well, and the filename fred would have been retained in the new directory.

After executing this command, there will no longer be a fred file in the current directory.

b) cp

cp fred wilma

This copies fred to a file named wilma.

cp fred flintstones/fred

This copies fred to a file named fred in the subdirectory flintstones.

c) rm

rm flintstones

This removes a file named flintstones.

rm -rf flintstones

This removes a directory named flintstones. The -r removes the directory, the -f forces it to remove files without asking you before it deletes each one.

2. Directory manipulation

In order to keep track of the possibly millions of files on-line, Unix systems have a directory tree, which enables meaningful classification of files. For example, the most essential system programs are kept in /bin/, user home directories are all under /home/, and everything having to do with the WWW is under /www/. More specifically, your home directory is /home/you/ and the directory for your WWW files is /www/htdocs/you/.

a) pwd

pwd This prints out your working directory: where you are. When you give a filename to a command without specifying some other directory, the filename is looked up, manipulated, or created in your current working directory.

b) mkdir

mkdir flintstones

This makes a subdirectory of the current directory named flintstones.

c) cd

cd flintstones

This changes the directory to the subdirectory named flintstones.

cd /home/flintstones

This changes the directory to the home directory of the flintstones.

cd /www/htdocs/flintstones

This changes the directory to the WWW directory of the flintstones.

cd

With no arguments, cd returns you to your home directory.

4) rmdir

rmdir flintstones This removes the subdirectory flintstones. The directory must be empty for this to work.

3. Account management

1) ln (redirecting file access)

Type ln -s fred.html index.html to redirect all file accesses from index.html to the file fred.html.

2) passwd (changing your password)

Type passwd to change your password.

3) zip/unzip

Type zip to zip files and unzip to unzip files. This program is compatible with the zip program for DOS. For example:

zip myzip file1 file2 file3

This puts the files file1, file2, and file3 into a new zip archive called myzip.zip. On the other hand, if you had the archive myzip.zip and wanted to get back the files:

unzip myzip

Typing zip or unzip by itself will give you a usage summary, showing nearly all the options availible.

4) du (disk usage)

The Unix command

du -s directory

shows how much disk space is used by a directory and everything below it. While we work on creating the complicated command needed to automatically check all the directories you are associated with, you can find out how much space is in use by the WWW files for a domain with

du -s /www/htdocs/domain

If you don’t have anything much in your home directory or mail spool, this comes close to the total space you have in use. (You would know if you did have other things in your home directory, and could use du -s $HOME to check on that.)

If you have an anonymous FTP area, also check

du -s ~ftp/my.domain

For example, snoopy.com might need to run some number of the following:

du -s /www/htdocs/snoopy
du -s ~ftp/snoopy.com
du -s $HOME

and add the results to find out how much space he’s using.

You might find it useful to use the -c command and group the paths

Example:

brown:~$ du -sc /www/htdocs/pir ~ftp/pir.com $HOME

5489    /www/htdocs/pir
4       /www/ftp/pir.com
13      /home/rmiller
5510    total

Actual results.

brown:~$ du -sc /www/htdocs/pir ~ftp/pir.com $HOME
5489    /www/htdocs/pir
du: /www/ftp/pir.com/bin: Permission denied
du: /www/ftp/pir.com/dev: Permission denied
du: /www/ftp/pir.com/etc: Permission denied
du: /www/ftp/pir.com/lib: Permission denied
4       /www/ftp/pir.com
13      /home/rmiller
5510    total

The numbers reported are kilobytes. A senior or RealAudio account gets to use about 51,000 blocks before having additional charges. A junior or telnet- only account gets about 5,100.

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