esources

1         eject :open the  cdrom

2         cat :  -e   add $ to the end of each line

         -n   number each line

         -T   display the character  jump  as  ^I

         -b   number the lines which unempty

3   sort:

4   tar :

     tar –cf archive.tar foo far   tar foo and far into archive.tar

     tar –tvf archive.tar        list all the files in archive.tar

     tar –xf archive.tar         extract all files in archive.tar

5   du :

      du  direction –h         display the memory which has been ocpied

6   uname –a       display all the system infomations

7   groupadd groupname     add group  groupname

groupdel groupname     del group  groupname

8   useradd username        add user  username

userdel username        del user   username

9   top :        display all the process in the system

10  df –h –T -a   display all the disk divisions

11  cal month year  display date

12  mount   -v    supply more information about mount

            - r    mount the dev as read-only

            -w    mount the dev as writeable

            -t vfat  only mount  filesystems such as vfat(fat32 in windows)

            -o loop  mount iso files

13  kill      stop process

           used with ps instruction which display all the processes running current

14  file      direction  filename

           verfy and display infomaton of the file we are to check

15  find    search some file

16  cat     display the comment of the file

17  rpm    -i    meaning install

           -v    will display detail information

           -h    #display processing

           -e    uninstall the rpm package or erase the package

           -q    check the package

           -U    update

           -a    display all the packages have been installed

           -p package   check the software package ‘package’

           -Va   check all the packages have been installed

           -Vp direction filename.rpm   check the installation

           -ql    check the install location