Introduction to redirection and pipes in Linux

Introduction to redirection and piping in Linux default output devices set by the redirection system: standard output, STDOUT,1 default input device: standard input, STDIN,0 standard error output: STDERR,2 standard input: keyboard standard output and error output: Imax O redirect standard input (stdin) in display linux: code is 0, use Standard error output (stderr): code is 2, use 2 > or 2 > >; ">" > > ">" > >: overwrite output > >: append output # set-C forbids override redirection on existing files Force override output Then use > | # set + C to disable the above functions "2 >" 2 > > "2 >: redirect error output 2 > >: append the correct and wrong ones into different files # ls / / varr > / tmp/var3.out 2 > / tmp/err.out# ls / varr > / tmp/var4.out 2 > / tmp/var4.out / dev/null trash can black hole device & >: redirect standard output Or error output to the same file (or 2 > & 1) "