Pipes

The unix system enables the user to efficiently connect two or more commands both. This connection is known as a pipe. The pipe enables to take the output from one command and feed it straightly into the input of another command. A pipe is effected through the character | (called pipe), that is placed among two commands. Whole the commands in a pipeline are executed in sequence. Unix handles the flow of data from one command to the next, producing the effect as if one command is being executed.

As an instance of a pipe, consider you wanted to count the number of files in your directory. Now we know which ls command show the names of all files and the command wc -l   is used to count the number of lines in a file. Then both these commands can be efficiently piped to get the desired result.

Let Consider the following

#ls | wc -l

10

The output denotes in which the directory holds 10 files. First, the ls command is executed to list the files, this output is then sent by the pipe as an input to the wc -l command, that is executed to provide the number of files. The last output is the output of the last command.