问题请教

Brevity

在看《linux shell脚本攻略》，书上说 cmd 2>&1 output.txt和cmd &> output.txt功能一样，但是在ubuntu环境下，前面一个语句不能执行完成，后面一个能够执行完成。

这时咋回事？？两个语句的功能到底一样不？

Brevity

2楼的，我的前面一个语句有错误？

hbmhalley

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

man bash(1)

shell_heaven

a:  
    command &>$filename

b:
    command >$filename  2>&1

c:
    command 2>$filename  >&2