Filter (software)

Filters are commands in operating systems that receive input from stdin the device, process and write its result to the device stdout. The term of the filter originates from the Unix operating system, but has been adapted by Microsoft in MS- DOS and is therefore to be found in the DOS derivatives. The operation of filters is still available in Windows 7.

To call filtering the issuing command through a pipe character | to separate them from the filter " ".

Operation

A classic filter on Unix is grep. This filter causes the output rows that contain a certain keyword.

Cut-d :-f 1 / etc / passwd | grep foo This command line searches for registered Unix users that have the string " foo" as part of their user name.

Under DOS / Windows a similar command looks like this:

Type c: \ autoexec.bat | find " echo" open the c: \ autoexec.bat file and returns all rows that contain the word " echo".