Regular users do not have permissions to alter files, however the super user can do any changes to the critical system files. For most of the times, one must avoid logging as a root user but at times one needs to login as a root user itself. Here, a small mistake could potential cause irreversible damage to the system. Take an example you are deleting a file & enter the following;
# rm -rf / etc/sysconfig/network-scripts/ifcfg-eth0:0
Noticed the space after ‘/’? That’s not intentional & it got mistyped in haste. Now, if the root user hits enter without correcting his mistake, it will lead to deletion of the entire root directory. You wouldn’t want that. However there is a simple command which prevents root user from deleting files or directories. You can set it on files or directories which you perceive to be important.
The command sets a certain attribute onto a file. These are special attributes over the regular file permissions. The attribute can be only set & unset by a root user.
# chattr +a filename
Now try doing,
# rm -rf filename
You will get,
rm: cannot remove ‘filename’ : Operation not permitted
You can do same on directories.
# chattr +a directory
This will also have an effect on the subsequent sub-directories in the specified directory. However, with the append(a) option, the file can still be altered using the append command. So to avoid that, use the immutable(i) switch instead of (a).
# chattr +i filename
The file can be now deleted nor written to(cannot be appended too).
To unset any of these attributes, simply use minus(-) along with the attribute you specified & file name/directory name.
# chattr -i filename
# chattr -a /directory/
Set this attribute on critical files & directories and you may avoid a potential doom’s day.
There are times when you need to post the outcome of a particular command(s) from a shell on a forum or somewhere else. It might be for troubleshooting or demonstration. However, copy-paste is not exactly a good option if your shell is filled with tons of information. Not to mention, you would spend a lot of time just selecting the text & then pasting it into a word processor. Wouldn’t life be easy if there would be a script which would gather all the data from a terminal & save it to a file? It does exist.
Before starting to run the command(s) whose output you wish to capture, enter;
$script -a filename
You will get,
[shuttertux@localhost ~]$ script -a filename
Script started, file is filename
Now one can begin entering the required commands. Once done, type;
[shuttertux@localhost ~]$ exit
Script done, file is filename
Now you can view the output file simply by,
Wasn’t that easy? Just remember, the output file is saved in your present working directory.
Star-trail photographs are mind boggling to look at. Its one of the most beautiful vista of nature. However most of the times when it comes to post-processing the photos after shooting a star trail can be a pain. Here is a small GIMP plugin which will help you elevate all that pain & concentrate more on shooting part of star trails. The plugin is known as ‘gimp-startrail-compositor‘. You can download it here.
Love in its purest form, ‘unconditional’ is the best. In our fast food society, seldom there is place for the unconditional love. If we exclude the love of mom for her child, then most other relations of love don’t hold strong to the bond of unconditional love. However, I feel privileged at the unconditional love showered by the people(developers, maintainers, users etc) of the “Free Software Foundation”.
The love which they put into their work so millions around the globe can experience a solid product. The compromises they make to fix the loopholes soon upon being discovered in software are many. My heart reaches out to people who are so devoted to their work. Who wake up every morning & put in their best. There is no appraisal or immediate reward but that does not let these people from doing what they do best. Its the effort & commitment of each person in the hierarchy who gives in his/her best which rubs off on the whole project. They work together in peace & utmost co-operation. Contrast this with the corporate world/society where most of the people are ever-ready to stomp on someone to gain a personal milestone in favor of the team’s success. Its a good lesson one can take from these people – “Do your Best & Team’s Success won’t be far off”.
At the end of the day, I feel so happy to be a part of it. Its not about the money I save from using free software. Its not about showoff/glitz factor in using free software. Its all about appreciating the good work of people involved & joining them. Its about helping to spread the word, that being free does not equates to poor. Though I’m still in my baby steps towards contribution to the free software foundation but I’m doing my bit. If everyone gives in a bit, then we’re looking at a tsunami of greatness. The Tsunami of Free Software sailing not only in computers & gadgets but in hearts around the globe. Happy Free Software Day! :-)
Over the time, your operating system tends to generate temporary files which get on accumulating in the temporary directories. This negatively affects the system responsiveness & off-course wastes disk space. Further, there are also other resources like browser caches, thumbnail caches & more which if not cleared from time to time make the system sluggish. An advance user may very well take control & go rectifying each of the above problems. However that would mean more time to clear up each individual thing. Here, steps in to rescue is KDE’s very own utility – Sweeper(Application>Utilities>Sweeper).
As the name suggests, Sweeper is a tiny utility which lets one clear all the unwanted clutter from the system. The interface of sweeper is ridiculously idiot-proof & all the options are self explanatory. Simply check whatever you wish to get rid off from your system & hit “Clean Up”. Sweeper is capable of clearing cookies, temporary files, thumbnail cache, browser cache, favicons, clipboard, recently used document list, recent applications etc.
From time to time, I recommend running Sweeper & letting it do its job. It will ensure you good disk resources & a responsive computer.