[ZZ] Linux redirection File

[ZZ] Linux redirection file/dev/null indicates an empty Device File> indicates the redirection location. For example, echo "123">/home/123.txt 1 indicates stdout standard output, the default value of the system is 1, so ">/dev/null" is equivalent to "1>/dev/null" 2 indicates stderr standard error & indicates equivalent meaning, 2> & 1, 2 is equivalent to 1>/dev/null 2> & 1 1>/dev/null. First, the standard output is redirected to an empty device file, that is, no information is output to the terminal. To put it bluntly, no information is displayed. 2> & 1 next, the standard error output redirection is equivalent to the standard output. Because the standard output has been redirected to the empty device file, the standard error output is also redirected to the empty device file. # Cat std. sh #! /Bin/sh echo "stdout" echo "stderr"> & 2 #/bin/sh std. sh 2> & 1>/dev/null stderr #/bin/sh std. sh>/dev/null 2> & 1 the output result of the First Command is stderr, because stdout and stderr are merged and redirected to/dev/null, but stderr is not cleared, so it will still be displayed on the screen; the second command has no output, because stderr is redirected to stdout again after stdout is redirected to/dev/null, in this way, stderr is also output to/dev/null Always go with the choice that scares you the most, because that's the one that is going to require the most from you!