I/O Redirection
Table 2.8 shows a complete list of I/O redirectors. (This table is also included earlier as Table 7.1.) Note that there are two formats for specifying standard output and error redirection: &>file and >&file. The second of these, and the one used throughout this book, is the preferred way.
Table B-8. I/O Redirectors
Redirector | Function |
cmd1 | cmd2 | Pipe; take standard output of cmd1 as standard input to cmd2 |
> file | Direct standard output to file |
< file | Take standard input from file |
>> file | Direct standard output to file; append to file if it already exists |
>| file | Force standard output to file even if noclobber is set |
n>| file | Force output to file from file descriptor n |
even if noclobber set | |
<> file | Use file as both standard input and standard output |
n<> file | Use file as both input and output for file descriptor n |
<< label | Here-document |
n > file | Direct file descriptor n to file |
n < file | Take file descriptor n from file |
>> file |
Direct file descriptor n to file; append to file if it already exists |
n>& | Duplicate standard output to file descriptor n |
n<& | Duplicate standard input from file descriptor n |
n>&m | File descriptor n is made to be a copy of the output file descriptor |
n<&m | File descriptor n is made to be a copy of the input file descriptor |
&> file | Directs standard output and standard error to file |
<&- | Close the standard input |
>&- | Close the standard output |
n >&- | Close the output from file descriptor n |
n <&- | Close the input from file descriptor ... |
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