Redirect simple application (enable and disable redirection)

The simple application of redirection (enable and disable redirection) is a simple example. today, you need to output errors to files and other normal data to the screen, LOG can be implemented in this way. /test. logexec3 & gt; & amp; 14 & gt; & amp; 22 & gt; $ LOG1 & gt; $ LOGechoaa... the simple application of redirection (enable and disable redirection) is a simple example. today, you need to output errors to files and other normal data to the screen, LOG =. /test. logexec 3> & 1 4> & 22> $ LOG 1 >>$ LOGecho aaaexec 1> & 3 2> & 4 echo bbb memory method: I also thought it would be meaningless to output 3 to the standard output. In fact, you need to understand this, that is, file descriptor 3 is assigned as a standard output. here we can experiment like this: LOG =. /test. logexec 3> & 1 4> & 2 2> $ LOG 1> $ LOGecho aaaecho ccc> & 3 exec 1> & 3 2> & 4 echo bbb, you can see that ccc is normal output, therefore, when executing exec 1> & 32> & 4, it can be understood that file descriptor 1 is replaced by file descriptor 3, thus enabling or disabling redirection in a script.