&> 等如 2>&1 , > 等如 1> ,那是縮寫,

1 是 STDOUT, 2 是 STDERR, 2>&1 就是 STDOUT 和 STDERR

同導向到同一檔案裡, 例

nc10@your-5554c55be4 ~

$ ls llllllll

ls: 無法訪問 llllllll: No such file or directory

nc10@your-5554c55be4 ~

$ ls llllllll 2> log.txt

nc10@your-5554c55be4 ~

$ ls page1.html > log2.txt

nc10@your-5554c55be4 ~

$ cat log.txt log2.txt

ls: 無法訪問 llllllll: No such file or directory

page1.html

nc10@your-5554c55be4 ~

$ ls llllllll page1.html > log3.txt 2>&1

nc10@your-5554c55be4 ~

$ cat log3.txt

ls: 無法訪問 llllllll: No such file or directory

page1.html

nc10@your-5554c55be4 ~

$ ls llllllll page1.html &> log4.txt

nc10@your-5554c55be4 ~

$ cat log4.txt

ls: 無法訪問 llllllll: No such file or directory

page1.html

nc10@your-5554c55be4 ~

$