This is a simple concept map for pipes and filters.
Examples
| In the pipeline a | b | c the output from process a becomes the input for process b. Then the output of process b becomes the input to process c. |
Some examples (from Matt Davis ) include:
A classic example of pipes and filters is to search the contents of a particular set of files for a string or pattern:
find . -type f -name "*.py" -print | xargs grep -n "speed of light"
In the above example the find command looks for all files ending in .py (Python source files) and then passes the names of those files to grep which searches for the ‘string speed of light’ and prints any matches with their line numbers.
Filters and pipes can also be used for numeric work. In the following command cut takes a column of numbers from a file called some_nums.txt, paste joins those lines together with the ‘+’ character, and then bc evaluates that mathematical expression:
cut -c 4-5 some_nums.txt | paste -sd + - | bc