Hi All,

Hope all of you familiar with grep command. Here is one more trick to solve the crossword puzzle using the grep command and the dictionary file.

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$ grep "^.ro..w.r.$" /usr/share/dict/words
 
broomwort
brownwort
crossword
crosswort
crownwork
crownwort
frontward
frostwork
frostwort

Just replace unknown character by . (dot) in the grep command.

bye

kamaraj

watch is used to run any designated command at regular intervals. It displays its output on a console (i.e., all-text mode display) or terminal window (i.e., a window in a GUI that emulates a console) that is temporarily cleared of all other content (i.e., prompts, commands and results of commands).

This makes it easy to observe the changing output of a command over time.

Example :

watch -d free -m

watch command will observe the free command and it will highlight the difference for each 2 seconds.

Output:

Every 2.0s: free -m                                                                                                                  Sun Dec 19 01:24:29 2010

             total     used       free     shared    buffers     cached
Mem:          1498     1038        459          0         48        644
-/+ buffers/cache:        345       1152
Swap:         1398          0       1398
 

TELNET (TELecommunication NETwork) is a network protocol used on the Internet.

TELNET is a client-server protocol, based on a reliable connection-oriented transport. This command will help us to find if a particular port on the server is open or not.

Example:

In the below example i am checking whether port # 22 is open or not in my system

[kamaraj@Kamaraj ~]$ telnet 127.0.0.1 22
Trying 127.0.0.1…
Connected to 127.0.0.1.
Escape character is '^]'.
SSH-2.0-OpenSSH_5.5
 

If you get the above message "Connected to 127.0.0.1" then it is open. If you get a message like "connection refused" then it the port is not open.

ps command:

This command is used to check the process running on the server. " ps " command will list all the running process with there respective process ID.

pstree command:

This command is also used the check the process on the server. " pstree " command will list all the running process in the form of a tree structure.

init─┬─NetworkManager─┬─dhclient
     │                └─2*[{NetworkManager}]
     ├─abrtd
     ├─acpid
     ├─atd
     ├─auditd─┬─audispd─┬─sedispatch
     │        │         └─{audispd}
     │        └─{auditd}
     ├─avahi-daemon───avahi-daemon
     ├─bluetoothd
     ├─bonobo-activati───2*[{bonobo-activat}]
     ├─clock-applet───{clock-applet}
     ├─console-kit-dae───4*[{console-kit-da}]
     ├─crond
     ├─cupsd
 

Also try the -p option for pstree

[kamaraj@Kamaraj ~]$ pstree -p
init(1)─┬─NetworkManager(1160)─┬─dhclient(2091)
        │                      ├─{NetworkManager}(1174)
        │                      └─{NetworkManager}(2092)
        ├─abrtd(1441)
        ├─acpid(1288)
        ├─atd(1474)
        ├─auditd(1629)─┬─audispd(1631)─┬─sedispatch(1643)
        │              │               └─{audispd}(1644)
        │              └─{auditd}(1630)
        ├─avahi-daemon(1178)───avahi-daemon(1179)
        ├─bluetoothd(1388)
        ├─bonobo-activati(1824)─┬─{bonobo-activat}(1832)
        │                       └─{bonobo-activat}(1933)
        ├─clock-applet(2069)───{clock-applet}(2074)
        ├─console-kit-dae(1532)─┬─{console-kit-da}(1533)
        │                       ├─{console-kit-da}(1534)
        │                       ├─{console-kit-da}(1536)
 

You all know, the Linux is free and open source operating system. So you can download the linux operating system from the respective websites.

As i know, UBUNTU team is distributing the CD's through post (that too free of cost)

Register yourself here and request the CD's and spread the operating system worldwide 🙂

https://shipit.ubuntu.com/

uptime gives a one line display of the following information. The current time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.

$ uptime
 10:00:26 up 12 min,  2 users,  load average: 0.26, 0.44, 0.39
 

This is the same information contained in the header line displayed by w(command)  

$ w
 10:00:23 up 12 min,  2 users,  load average: 0.29, 0.45, 0.39
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
kamaraj  tty7     :0               09:48     ?    50.38s  0.18s x-session-manag
kamaraj  pts/0    :0.0             09:58    0.00s  0.16s  0.00s w