170 ;;Quote: want to limit interprocess communication to a small number of well-defined methods; for uniformity, understandability, and reliability

170+;;Quote: UNIX pipes encourage small programs that are easily connected; good for human comprehension and computer performance

170 ;;Quote: UNIX processes communicate via shared open files, program arguments, exit codes, predefined files, and pipes

170 ;;Quote: a Unix shell command consists of arguments separated by blanks; the first specifies the command

170 ;;Quote: in UNIX, shell and executable programs appear to be invoked the same; a child process runs executable programs

170 ;;Quote: Unix searches for commands in user's directory, /bin directory, and /usr/bin directory

171 ;;Quote: UNIX commands expect preopened files for standard input, output, and error

171 ;;Quote: in Unix, many command arguments are file patterns which create a sorted list of matching filenames

172 ;;Quote: direct standard output to a variable in a shell program by '... | =d'

QuoteRef: mashJR_1976 ;;172 "Currently, five variables are assigned special meanings: ... $p permits alteration of the names and order of directory path names used when searching for commands.

172 ;;Quote: in a command line, $n is replaced by the n'th argument

174 ;;Quote: a UNIX shell file can trap interrupts with a goto, ignore them, or use the default handler

175 ;;Quote: about 75% of UNIX shell programs consisted of straight-line scripts

176 ;;Quote: about 30% of shell programs included both shell and non-shell commands; most in straight-line scripts

176 ;;Quote: approximately 80% of the commands issued in Programmer's Work Bench are from a shell program