How to append output to the end of a text file

Use >> instead of > when directing output to a file:

your_command >> file_to_append_to

If file_to_append_to does not exist, it will be created.

Example:

$ echo "hello" > file
$ echo "world" >> file
$ cat file 
hello
world

To append a file use >>

echo "hello world"  >> read.txt   
cat read.txt     
echo "hello siva" >> read.txt   
cat read.txt

then the output should be

hello world   # from 1st echo command
hello world   # from 2nd echo command
hello siva

To overwrite a file use >

echo "hello tom" > read.txt
cat read.txt  

then the out put is

hello tom

You can use the >> operator. This will append data from a command to the end of a text file.

To test this try running:

echo "Hi this is a test" >> textfile.txt

Do this a couple of times and then run:

cat textfile.txt

You'll see your text has been appended several times to the textfile.txt file.

Use command >> file_to_append_to to append to a file.

For example echo "Hello" >> testFile.txt

CAUTION: if you only use a single > you will overwrite the contents of the file. To ensure that doesn't ever happen, you can add set -o noclobber to your .bashrc.

This ensures that if you accidentally type command > file_to_append_to to an existing file, it will alert you that the file exists already. Sample error message: file exists: testFile.txt

Thus, when you use > it will only allow you to create a new file, not overwrite an existing file.