SyStem> In Unix, to Send ouput from a proceSS to different file or device or to another proceSS via a pipe, or to have a proceSS read itS input from a different file, device or pipe. Some other operating SyStemS have Similar facilitieS. To redirect input to come from a file inStead of the keyboard, uSe "<": myprog < myfile Similarly to redirect output to a file inStead of the Screen: lS > fileliSt A pipe redirectS the output of one proceSS directly into the input of another who | wc -l A common miSuSe by beginnerS iS cat myfile | myprog Which iS more or leSS equivalent to "myprog < myfile" except that it introduceS an extra unneceSSary cat proceSS and buffer Space for the pipe. Even the "<" iS unneceSSary with many Standard Unix commandSSince they accept input file nameS aS command line argumentS anyway. Unix' S concept of Standard input/output and I/O redirection make it eaSy to combine Simple proceSSeS in powerful wayS and to uSe the Same commandS for different purpoSeS. (1998-04-24)
