linux: redirecting the data flow

Redirecting the data stream: data from one place to another.

1. Standard Input: Code 0: <, <<

2. Standard Output: Code 1:> >>

3. The standard error: Code 2: 2> 2 >>

Note: When transferring data to another file, when the file does not exist, create a file when the file exists, the contents of the file 1 will be refreshed.

Sample one: Check / file and output the information it into the ~ / File file
LS / & gt; ~ / file Note: In this way there is no screen output, because the output data file in the file.

Sample 2: Using the general status of the search / if there is .bashrc file home, the correct output and error output into separate files.
find /home -name .bashrc &got; list_right 2> list_error
This put the right information into the list_right, the wrong information into list_error, and will not export any information on the screen.

/ Dev / null Trash and Special Black Hole writing device

Applies to already know is wrong, but you want to erroneous information is not displayed and stored, and / dev / null can eat any information leading to it
Sample one: throw away the erroneous data, the correct information is displayed
find /home -name .bashrc &got; /dev/null

The error message and correct information in the same file
First in writing:
find /home -name .bashrc > list 2>&1
The second writing:
find /home -name .bashrc &> list

keyboard input

Standard Input: <, <<

 

Sample one: Use the cat command to create a file
cat > catfile
testing
cat file test and then [Ctrl + d] leave, this file is created and edited the

Sample two: one sample changed by keyboard input as input file
cat &gt； file1 &lt； file2
This put spread file1 file2 content

And that meant the end of the input <<