Basic Unix Commands

Login Process: Login: user2Password: ******** $ à Normal user prompt# à System admin prompt Commands: $ logname          à  to check present working user.User2$ clear                à to clear screenWe can also use cntrl+l to clear screen$exit                   à to quit from user session.Help Facility:Syn:  1. $ man [command name]    à displays use and options of the command.Ex:  $ man dateDisplays date command usage and options.$ man cal$ man man  2. $ pwd               à to display the present working directory      /home/user2  3. $ cal                       à to display calendar (current month calendar)         $ cal 2000            à to display 2000 year calendar.        $ cal 08 2010        à august month of 2010 year calendar        $ cal 78                 à 78 year calendar.        $ cal 1                   à 1st year calendar.        $ cal 10000           à illegal year usage range upto 1-9999 only     If you pass only one parameter after cal it considers it as year. If you pass two parameters 1st parameter is month and 2nd parameter is year.  4.  $ date                 à to display date (displays system or server’s date which it is working)   Options:        $ date +%m        à to display month        12       $ date +%h          à to display name of the month        December       $ date +%d          à to display day of month (1 to 31)       22      $ date +%y           à to display last two digits of the year.      11      $ date +%Y          à to display four digits of the year.      2011      $ date +%D        à to display date in MM/DD/YY format.      12/22/11      $ date +%T        à to display time in the format hh:mm:ss     12:30:54H, M and S à this options are used to display hour, minutes and seconds.  5.  $ who              à to display present working users.          User2 tty1          User3 tty3          User4 tty0Here tty is the UNIX naming for terminals.LINUX naming for terminals is Pts1, Pts2 ……Terminal number is used identify the clients.  6.  $ finger              à displays more information about the users like name of the user, phone number, idle time etc ..,  7.  $ who am i         à displays current working users details       User2   tty1    2011-11-12    17:20   ip address  8.  $ whoami         à displays current working user without details       User2  9.  $ tty                 à to display terminal type 10. $ sleep [time in sec]      à to take the shell into sleeping state.       $ sleep 5             For 5 seconds the shell will be going to sleep state11. Executing multiple commands      $ cmd1; cmd2; cmd3; cmd4   Ex:  $ ls; sleep 5 ; dateHere first list of the files will be displayed then it goes to sleeping state for 5 seconds and it displays date. 12. Wild card characters       A number of characters are interpreted by the UNIX shell before any other action takes place. These characters are known as wildcard characters. Usually these characters are used in place of filenames or directory names.*             An asterisk matches any number of characters in a filename, including none.?             The question mark matches any single character.[ ]            Brackets enclose a set of characters, any one of which may match a single character                at that position. -             A hyphen used within [ ] denotes a range of characters.~             A tilde at the beginning of a word expands to the name of your home directory. If                  you append another user's login name to the character, it refers to that user's home               Directory. Here are some examples:1.      cat c*        à displays any file whose name begins with c including the file c, if it exists.2.      ls *.c         à  lists all files that have a .c extension.3.      cp ../abc?. à copies every file in the parent directory that is four characters long and                     begins with abc to the working directory. (The names will remain the same)4.      ls abc[34567] à lists every file that begins with abc and has a 3, 4, 5, 6, or 7 at the end.5.      ls abc[3-7]      à does exactly the same thing as the previous example.6.      ls ~                 à lists your home directory.7.      ls ~user1        à lists the home directory of the user with the user id user1.8.      $ ls file [1-9] [1-9] à in the filename 5th char should be 1-9...

Read more »