Answer:

GNU parallel is a tool for executing jobs in parallel. It is not part of standard Linux distribution yet, so it is so worth to install it.

You can download the latest version from: http://ftp.gnu.org/gnu/parallel/

E.g.

# wget http://ftp.gnu.org/gnu/parallel/parallel-20101202.tar.bz2
# tar -jxvf parallel-20101202.tar.bz2
# cd parallel-20101202
# ./configure
# make && sudo make install

Example usages:

#  echo -e "a\nb\nc"  | parallel echo "foo"

foo a
foo b
foo c

Answer:

Underline the current editing line in vim is very useful, to do so, follow the guide below.

1. Press [ESC] to get into command mode

2. Enter :set cursorline

Answer:

To display the currently editing filename in the title of terminal of vim, you can try the tricks below:

1. Press [ESC] to get into command mode

2. Enter :set title

Answer:

To remove ownloaded archive files from apt-get to save spaces, try the following command:

# sudo apt-get clean

So all the unneeded archive files will be removed.

Answer:

7zip is a well known compression program if you need a very small file size, i.e. high compression ratio.

To install under Ubuntu/Debian:

# sudo apt-get install p7zip

To compress a file

# p7zip test.txt

To decompress a file

# p7zip -d test.txt.7z

Answer:

If you opened an UTF-8 file, you need to let vim know by using the command below, after entering the command mode by pressing Esc + :

: set encoding=utf8

Answer:

Vim support code formatting and auto indentation - if you tell Vim to know the filetype (either by file extension, or by setting the filetype)

e.g. A simple C program (test.c)

#include 

main()
{
for(int i=0;i<10;i++)
{ 
printf ("Hello World!\n");
}
}

Then type following in Vim command mode (by pressing Esc):

gg=G

Now the code will be formatted to:

#include 

main()
{
    for(int i=0;i<10;i++)
    {
        printf ("Hello World!\n");
    }
}

Answer:

Burn an ISO images to CDR in Ubuntu is as easy as the following command:

# sudo cdrecord dev=/dev/scd0 driveropts=burnfree -v -data my_file.iso

Answer:

Previous article told you how perform checksum on a file. How about to perform checksum on a folder?

A simple solution is to install md5deep

# sudo apt-get install md5deep

To perform checksum on a particular folder (input),

#  md5deep -l -r input

26ab0db90d72e28ad0ba1e22ee510510  input/2.txt
6d7fce9fee471194aa8b5b6e47267f03  input/3.txt
b026324c6904b2a9cb4b88d6d61c81d1  input/1.txt

That's so easy.

Reference: http://md5deep.sourceforge.net/

Answer:

If you have a very large file and want to split into multiple smaller files, split command can do the job for you.

# split -l 10 text.txt

The above command split the file text.txt into a multiple files (xaa, xab, xac...), which contains at most 10 lines per file.