Input - Output redirection in Shell Scripts

Using shell scripts, we can redirect
- the output of a command to a file
or
- redirect an output file as an input to other commands.

There are mainly 3 types of redirection. They are >,>>,<

Input - Output redirections in Linux Shell Scripting

1. >

Example:
ls > ls-file

The above command will redirect the output of the " ls " to the file " ls-file ".
If the file " ls-file " already exist, it will be overwritten. Here you will loose the existing data.

2. >>

Example:
date >> ls-file

The output of the date command will be appended to the file " ls-file ".
In this case you will not loose any data. The new data gets added to the end of the file.

3. <

Example:
cat < ls-file

This redirection symbol takes input from a file.
In the above example the cat command takes the input from the file " ls-file " and displays the "ls-file" content.