Syntax Usage
sort <filename> Sort the lines in the specified file
cat file1 file2 | sort Append the two files, then sort the lines and display the output on the terminal
sort -r <filename> Sort the lines in reverse order

To remove duplicate entries from some files, use the following command:

sort file1 file2 | uniq > file3

To count the number of duplicate entries, use the following command:

uniq -c filename

PASTE:
To paste contents from two files one can do:

$ paste file1 file2

The syntax to use a different delimiter is as follows:

$ paste -d, file1 file2
Common delimiters are ‘space’, ‘tab’, ‘ ’, ‘comma’, etc.

JOIN:
To combine two files on a common field, at the command prompt type

join file1 file2

and press the Enter key.

SPLIT:
By default split breaks up a file into 1,000-line segments. The original file remains unchanged, and set of new files with the same name plus an added prefix is created. By default, the x prefix is added. To split a file into segments, use the command

$ split <file_to_split_> <name files="" of="" split=""></name></file_to_split_>