20 Unix Command Line Tricks – Part I

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Let us start new year with these Unix command line tricks to increase productivity at the Terminal. I have found them over the years and I'm now going to share with you.

 

Deleting a HUGE file

 

I had a huge log file 200GB I need to delete on a production web server. My rm and ls command was crashed and I was afraid that the system to a crawl with huge disk I/O load. To remove a HUGE file, enter:

> /path/to/file.log

# or use the following syntax

: > /path/to/file.log

 

# finally delete it

rm /path/to/file.log

 

Want to cache console output?

 

Try the script command line utility to create a typescript of everything printed on your terminal.

script my.terminal.sessio

 

Type commands:

ls

date

sudo service foo stop

 

To exit (to end script session) type exit or logout or press control-D

exit

 

To view type:

more my.terminal.session

less my.terminal.session

cat my.terminal.session

 

Restoring deleted /tmp folder

 

As my journey continues with Linux and Unix shell, I made a few mistakes. I accidentally deleted /tmp folder. To restore it all you have to do is:

mkdir /tmpchmod 1777 /tmpchown root:root /tmpls -ld /tmp

 

Locking a directory

For privacy of my data I wanted to lock down /downloads on my file server. So I ran:

chmod 0000 /downloads

 

The root user can still has access and ls and cd commands will not work. To go back:

chmod 0755 /downloads

 

Password protecting file in vim text editor

 

Afraid that root user or someone may snoop into your personal text files? Try password protection to a file in vim, type:

vim +X filename

............

 

 

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