Table B-9. 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 n
|
|
n>&word
|
If n is not specified, the standard output (file
descriptor 1) is used; if the digits in word do not specify a file
descriptor open for output, a redirection error occurs; as a special
case, if n is omitted, and word does not expand
to one or more digits, the standard output and standard error are
redirected as described previously
|
|
n<&word
|
If word expands to one or more digits, the file descriptor denoted by
n is made to be a copy of that file descriptor;
if the digits in word do not specify a file descriptor open for
input, a redirection error occurs; if word evaluates to -, file
descriptor n is closed; if n is not specified,
the standard input (file descriptor 0) is used
|
|
n>&digit-
|
Moves the file descriptor digit to file descriptor
n, or the standard output (file descriptor 1) if
n is not specified
|
|
n<&digit-
|
Moves the file descriptor digit to file descriptor
n, or the standard input (file descriptor 0) if
n is not specified; digit is closed after being duplicated to
n
|
