Linux Operation Commands

Chap.1 Usefule Commands

 

1, How to check your Linux release version?

     A: cat /etc/issue

Example:

     28849079@cnbjlx1288:~$ cat /etc/issue
     Ubuntu 9.10 \n \l

2, How to check the detailed release version of your Linux?

    A: lsb_release -a     ---------> I think the "a" is equal to "all"

Example:

   28849079@cnbjlx1288:~$ lsb_release -a
   No LSB modules are available.
   Distributor ID:    Ubuntu
   Description:    Ubuntu 9.10
   Release:    9.10
   Codename:    karmic

 

3, How to check the Linux Kernel version? take Ubuntu as example

    A: uname -r          ----------> r == release,  I think

 Example:

    28849079@cnbjlx1288:~$ lsb_release -a
    No LSB modules are available.
    Distributor ID:    Ubuntu
    Description:    Ubuntu 9.10
    Release:    9.10
    Codename:    karmic

4, How to check a file's access attribution ?

    A: ls -l <filename>      ------->ls == list

Example :

    28849079@cnbjlx1288:~/Downloads$ ls -l The\ Unix\ Programming\ Environment\ .pdf
    -rw-r--r-- 1 28849079 domain^users 839306 2010-04-23 10:18 The Unix Programming Environment .pdf
Comments on "-rw-r--r--":

   1) The first "-" in result means it's a file, should be "d" if it is a directory.

   2) "rwx" describes the related user right on this file, r == read, w == write, x == execute.

   3) the first "rwx" is indicates the current user, the 2nd "rwx" indicates group user, the 3rd "rwx" means other user.

 

5. How to change a file's access attribute ?

    A: chmod xxx <filename>

Example:

   chmod rwxr--r-- file.txt    or

   chmod 744 file.txt 

6. How to create a symbolic links ?
    A: ln -s src newfile       ------> src is the existing file, and newfile is the one that to be created
Example:

    touch testdir/testfile

    ln testdir/testfile CopyOftestfile

    

7. How to change password ?

    A: passwd

Example:

    ...

 

8. How to rename file ?
    A: mv                                  -----> mv == move

Example:

   mv oldname newname      -----> oldname must exist

9. How to copy a file or a directory ?

    A: cp                                  -----> cp == copy

Example:

    cp src dest

 

10. How to print a file content on screen

    A: cat

 Example:

    cat test.txt                           -----> test.txt contains some simple charactics.

Others:

   head & tail                            -----> head print the beginning n lines, and tail for the end n lines.

 

11. How to check the system process information ?

      A: ps

Example:

      NA

 

12. How to terminate a process ?

     A: kill

Example:

    kill pid                                -----> pid is a process id, it can be retreived via the above command ps

13. How to run a job in background ?

    A: with a postfix '& '

Example:

    sleep 10

    sleep 10 &                            -----> with '&' will not block the current process

14. Difference between '>' & '>> ' & ‘>|’

     A: All of them are redirection operation, '>' overwrite and '>>' append, both of them would create a new file if no the specific file is not exist, '>|' would force redirection and overwrite the destination file.

Example:

 

15.  The functionality of pipe '|'

    A: A pipe, as a classic method of interprocess communication, sends the <stdout> of one process to the <stdin> of another. In a typical case, a command, such as cat or echo, pipes a stream of data to a "filter" for processing, like:

Example:

         cat $filename1 $filename2 | grep $search_wordNotes:

Note: The stdout of each process in a pipe must be read as the stdin of the next. otherwise, the data stream will block.

16. The functionality of  dash '-'

     A: redirection from/to stdin or stdout, Where a filename is expected, dash '-' redirects output to stdout, or accepts input from stdin, rather than from a file.

Example:

      /BashWorkSpace$ file --mime-type -                                 ----> with a dash '-' in the end of the command
      你好                                                                                        ----> This is user input in stdin(terminal)
      /dev/stdin: text/plain

17. 查看打开的文件

      lsof  ----> list open files

      http://www.ibm.com/developerworks/cn/aix/library/au-lsof.html

 

13. TBD...

more, less, cc, grep, ps, which, env

 // lp, more, less ?

 

查找文件find:

find DIR [OPTIONS] [NAME]

find ~/ -size +1000c

find ~/ -size -1000c

find / -name http_conf*.c 2>/dev/null

find / -size +1000c -and -atime -1

others: -atime -cmin .....

http://wenku.baidu.com/view/c2be82254b35eefdc8d3336a.html

 

 

 chown, chgrp    ----> change owner, change group
       find        Search for les from a speci ed directory using various criteria.
       locate    Fast search in a global le database for les containing a search-string.
       whereis  Look for a command and its documentation on the system.

       du  -->disk usage
       df  

       ps   - process
       vmstat  --> virtual memory status : list kernel vm stastics
       netstat  -> network status/stastics: list network connection and stastics

       hostname -> show the name of this host

Chap.2 Control Characters

change the behavior of the terminal or text display. 

Ctrl + l  => Clear

Ctrl + c => Break, terminate a foreground job.

Ctrl + d => Log out from a shell; In vi, it scroll half screen 

Ctrl + b => Backspace, In vi, it scroll back a screen      

Ctrl + f =>  In vi, it scroll foward a screen

Ctrl + u =>  Erase a line of input, from the cursor backward to beginning of line. In some settings, Ctl−U erases the entire line of input, regardless of cursor position.
Ctrl + W => Erases from the character under the cursor backwards to the first instance of whitespace. In some settings, it erases backwards to first non−alphanumeric character.


 

Chap. 3 Tips

 

Q: manual about apt-get

 http://baike.baidu.com/view/1580236.htm

 

Q: Linux下运行交互式脚本的时候用回车键无法删除前面的字符

解决方法：用Ctrl + Backspace