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Like many other thing in Linux ,you can see the same thing in different way.
This is a handy way to find which modules are loaded with Apache web server.
This command will reveal login has been made to the system as well as when the reboot occurs. It uses a file called /var/log/wtmp,which captures all the information about the successful login and reboot information. It has many switch ,by which you can get an idea when people login how long they stay.
This is wonderful perl script to check the web server security and vulnerability .Get it from here :http://www.cirt.net/nikto2
Here are some key features of "Nikto":
? Uses rfp's LibWhisker as a base for all network funtionality
? Main scan database in CSV format for easy updates
? Determines "OK" vs "NOT FOUND" responses for each server, if possible
? Determines CGI directories for each server, if possible
? Switch HTTP versions as needed so that the server understands requests properly
? SSL Support (Unix with OpenSSL or maybe Windows with ActiveState's Perl/NetSSL)
? Output to file in plain text, HTML or CSV
? Generic and "server type" specific checks
? Plugin support (standard PERL)
? Checks for outdated server software
? Proxy support (with authentication)
? Host authentication (Basic)
? Watches for "bogus" OK responses
? Attempts to perform educated guesses for Authentication realms
? Captures/prints any Cookies received
? Mutate mode to "go fishing" on web servers for odd items
? Builds Mutate checks based on robots.txt entries (if present)
? Scan multiple ports on a target to find web servers (can integrate nmap for speed, if available)
? Multiple IDS evasion techniques
? Users can add a custom scan database
? Supports automatic code/check updates (with web access)
? Multiple host/port scanning (scan list files)
? Username guessing plugin via the cgiwrap program and Apache ~user methods
Sometime you need to run firefox from the command just to rectify something about it.Means,if some of the addon broke you firefox setting or theme broke your ff setting then fall back to commandline i.e shell and type the mentioned command. It will open up an information box with few option along with the checkbox besides them(means you can select them) to start the web browser in safe mode.Besically deactivating all the addon and theme,except the default one.Once you are done/rectified thing ..close that session and reopen the browser normally.It should work.
Once it is connected to the remote server by that ssh protocol,the mentioned command will start working on that server.
If you follow my other posting regarding "vipw" and "vigr' then no explanation required.It has done the same thing as did with those two command.Open the /etc/sudoers file and attach a lock with it. Once you are done with it ,the lock gets released and the changes reflected to the original file.It will open a tmp file in vi editor to give you the chance to edit the sudoers file securely.visudo parses the sudoers file after the edit and will not save the changes if there is a syntax error. Upon finding an error, visudo will print a message stating the line number(s) where the error occurred and the user will receive the "What now?" prompt. At this point the user may enter "e" to re-edit the sudoers file, "x" to exit without saving the changes, or "Q" to quit and save changes. The "Q" option should be used with extreme care because if visudo believes there to be a parse error, so will sudo and no one will be able to sudo again until the error is fixed. If "e" is typed to edit the sudoers file after a parse error has been detected, the cursor will be placed on the line where the error occurred (if the editor supports this feature).
PS: Although I have had experienced myself and few people shown to me that it behaves badly in some distribution ,noteably SLES.But the problem can be rectified with little caution.
If you follow my previous posting regarding "vipw" then no explanation required.The same method goes behind this command also.It will open an tmp file in vi editor to give you the enlisting to edit the group file.And most importantly to attach a lock with it.Once you are done ,the lock is released and the changed reflected to the original file.So you can securely edit the group file over the network without the fear of being tampered .
Now a bit of explanation required for this command.Once you type the command it opens up an vi editor with an temporary file enlisting the password file information .So if you make an change it will not reflected in the passwd file until you save the file.The reason behind using this command over other way to view the password file in network environment is that it locks the password file when you start working with it.So no one can temper with it during that period.Once you are done(means you save the tmp file) ,it will release the lock associated with it.I think it's a better mechanism to view the sensitive data like passwd file.Never ever use other tool like cat, nano or any other means.
After you install slocate ,the first thing you have to do with it to initialise the database by issuing a command " slocate -u" . And then onwards just give the filename or dirname as a argument to the slocate command will reveal the files/dirs location in the system along with path.Moreover over it's an securely way of looking into the file system.
A wonderful command line utility to check the internet usage. It has got so many useful switch to display the data you want.Please visit the man page to get all the information.Get it from this website http://humdi.net/vnstat
To get the connection information of protocol tcp and extended infortmation.
As mentioned in the summery that it is a powerful command to monitor system activity in great way. It has got the power of vmstat,iostat,mpstat,df,free and sar.Instead of firing each single command separately ,one can fire one single command to get all the info at once.But there is a way to get the individual information too. Please see the man page . You can get it from here : http://dag.wieers.com/home-made/dstat/
Add this to your $HOME/.bashrc file. It will only set this prompt if it is running inside screen ($WINDOW var is set)
Looks like this...
Puts words on new lines, removing additional newlines.
Simply translates whitespace to newlines. Could be enhanced to compress out extra newlines, but that might be better handled in the next tool down the pipe, with eg uniq(1).
Found this one little more for me. This one removes the perl dependency (from command 2535).
Source for command : http://www.earthinfo.org/linux-disk-usage-sorted-by-size-and-human-readable/
This command displays a clock on your terminal which updates the time every second. Press Ctrl-C to exit.
A couple of variants:
A little bit bigger text:
watch -t -n1 "date +%T|figlet -f big"
You can try other figlet fonts, too.
Big sideways characters:
watch -n 1 -t '/usr/games/banner -w 30 $(date +%M:%S)'
This requires a particular version of banner and a 40-line terminal or you can adjust the width ("30" here).
With this command you can use shell variables inside sed scripts.
This is useful if the script MUST remain in an external file, otherwise you can simply use an inline -e argument to sed.
This is a working version, though probably clumsy, of the script submitted by felix001. This works on ubuntu and CygWin. This would be great as a bash function, defined in .bashrc. Additionally it would work as a script put in the path.