The example programs in this folder are all "filters".
They are programs that read from standard input and
write to standard output. A filter program will usually
do some manipulation of what it has read from standard
input before it writes it to standard output.

Use these examples to experiment with I/O redirection
and, more importantly, with "pipes". That is, use pipes
to combine several filters together.

C:\> java Double < Echo.java | java Reverse

C:\> java Double | java ToUpperCase | java Reverse

C:\> java FilterN 2 | java ToUpperCase | java Reverse

C:\> java Twiddle < Echo.java | java ToUpperCase | java Double  | java RemoveVowels > text.txt