15.E: Piping with |

15: File Utilities

15.C: Redirecting Input and Output

On the last page we made use of the < symbol and the catcommand. We will now introduce another symbol, << which stands for append standard output to. This symbol is very similar to the redirect standard output symbol, except that instead of creating a new file (or erasing an existing one) it adds the text to the end of the file.

While this symbol has many uses we will once again show it in combination with the cat command. To add README.first to the text.old file, simply use Readme.first as the input file and text.old as the appended file.
> cat README.first >> old.text

Use the head command to view the file. (Quiz)
Review the head command

The cat command and the redirection symbols are very versatile and powerful commands that you will find many uses for in Unix. For additional ideas on how to use the cat command see your man pages. For additional ideas on redirection, let your imagination and your neighbors be the guide. If you are experimenting with redirection, be careful not to destroy your files. You may want to make a backup of the directory you are working in before you experiment.

On the next page we will talk about piping which is the close cousin of redirection.

15.E: Piping with |

15: File Utilities

15.C: Redirecting Input and Output