command-line

You don’t have to type a range of numbers by hands!

BASH already has a built-in utility, named seq, for generating and printing a sequence of numbers.

Generate a sequence of numbers

Syntax: seq [OPTION]… FIRST
Syntax: seq [OPTION]… FIRST LAST

Print a sequence of numbers from 1 to 10:

$ seq 1 5
1
2
3
4
5

Generate a sequence of numbers with increment

Syntax: seq [OPTION]… FIRST INCREMENT LAST

Print a sequence of numbers from 0 to 20 with increment 5:

$ seq 0 5 20
0
5
10
15
20

Equalize width by padding with leading zeroes

Syntax: seq -w…

Equalize width by padding with leading zeroes:

$ seq -w 1 10
01
02
03
04
05
06
07
08
09
10

Use another separator

Syntax: seq -s SEPARATOR… – use SEPARATOR to separate numbers.

Default separator is a new line – "\n".

Use space to separate numbers:

$ seq -s " " 1 10
1 2 3 4 5 6 7 8 9 10

Here are the best ways of finding and counting the number of files or folders in a particular directory.

Count the number of files in a current directory

Using “ls” command:

This method is the best, if you need to count a large number of files.

$ ls -f . | wc -l

This command also enables -a option, so . , .. and other files starting with . , will be counted.

Using “find” command:

$ find . -type f  -maxdepth 1 | wc -l

Count the number of files recursively

The following command recursively counts the number of files in a current directory and all its sub-directories:

$ find . -type f | wc -l

Count the number of folders recursively

The following command recursively counts the number of folders in a current directory and all its sub-directories:

$ find . -type d | wc -l

Count the number of files by “file type”

The following command recursively counts the number of files, with “.txt” extension, in a current directory and all its sub-directories:

$ find . -type f -name "*.txt" | wc -l

Finding the largest files is extremely useful especially when you you’re low on disk space and want to free it up.

The best way to find the largest files on your Linux system is to use the command line.

Actually there is no simple command to list the largest files in Linux.

However, you can easily find the largest files, using a combination of the several simple commands.

Find The Largest Files in Linux

Run the combination of the following commands to find the largest files on your Linux system, beginning from the <DIR> directory (change <DIR> to whatever directory you need), and list top 10 of them.

$ find <DIR> -mount -type f -ls 2> /dev/null | sort -rnk7 | head -10 | awk '{printf "%10d MB\t%s\n",($7/1024)/1024,$NF}'

Find 10 largest files, starting from ‘/’ (root)

$ find / -mount -type f -ls 2> /dev/null | sort -rnk7 | head -10 | awk '{printf "%10d MB\t%s\n",($7/1024)/1024,$NF}'

       106 MB	/var/lib/mysql/ibdata1
        94 MB	/usr/lib/locale/locale-archive
        41 MB	/scripts/20130206-015833.tar.gz
        41 MB	/scripts/20130206-004839.tar.gz
        41 MB	/scripts/20130206-130400.tar.gz
        41 MB	/scripts/20130206-000442.tar.gz
        41 MB	/scripts/20130206-132019.tar.gz
        41 MB	/root/20130208-133954.tar.gz
        33 MB	/var/log/messages-20130303
        32 MB	/var/lib/rpm/Packages

Find 10 largest files, starting from ‘/home’

$ find /home -mount -type f -ls 2> /dev/null | sort -rnk7 | head -10 | awk '{printf "%10d MB\t%s\n",($7/1024)/1024,$NF}'

      3007 MB	/home/user/Desktop/share/linux-65835.iso
       448 MB	/home/user/Pictures/Turkey/SAM_4590.AVI
       266 MB	/home/user/Pictures/Turkey/SAM_4588.AVI
       173 MB	/home/user/Camera/VID_20130909_120713.mp4
       152 MB	/home/user/Camera/VID_20130909_115427.mp4
       133 MB	/home/user/Camera/VID_20130909_210904.mp4
       133 MB	/home/user/Pictures/Paris/VID_20130928_182431.mp4
       131 MB	/home/user/Pictures/Turkey/SAM_4597.AVI
       129 MB	/home/user/Pictures/Turkey/SAM_4641.AVI
       127 MB	/home/user/Desktop/tmp/Camera/VID_20130911_164440.mp4