我从中没有看到任何word可以是文件名的描述，只说了word可以是1~2位数字或者是-。所以你用文件名当word应该是不正确的用法。Duplicating File Descriptors
The redirection operator
[n]<&word
is used to duplicate input file descriptors. 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.
The operator
[n]>&word
is used similarly to duplicate output file descriptors. 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.
我写了个非常简单的程序进行验证Redirecting Standard Output and Standard Error
This construct allows both the standard output (file descriptor 1) and the standard error output (file descriptor 2) to be redirected to the file
whose name is the expansion of word.
There are two formats for redirecting standard output and standard error:
&>word
and
>&word
Of the two forms, the first is preferred. This is semantically equivalent to
>word 2>&1
代码： 全选
$ cat a.c
#include <stdio.h>
int main() {
printf("xxx");
while(1);
return 0;
}
$ gcc a.c
$ ./a.out 1>&file &
[1] 12417
$ ls -l /proc/12417/fd/*
lrwx------ 1 xxx xxx 64 2011-06-13 22:02 /proc/12417/fd/0 -> /dev/pts/0
l-wx------ 1 xxx xxx 64 2011-06-13 22:02 /proc/12417/fd/1 -> /home/xxx/file
l-wx------ 1 xxx xxx 64 2011-06-13 22:02 /proc/12417/fd/2 -> /home/xxx/file