UNIX中$@和$*什么区别？ 当在脚本中回显时，它们似乎都产生相同的输出。
一个区别是他们如何处理输出上的IFS变量。
#!/bin/sh echo "unquoted asterisk " $* echo "quoted asterisk $*" echo "unquoted at " $@ echo "quoted at $@" IFS="X" echo "IFS is now $IFS" echo "unquoted asterisk " $* echo "quoted asterisk $*" echo "unquoted at " $@ echo "quoted at $@"
如果你这样运行： ./demo abc def ghi ，你会得到这个输出：
unquoted asterisk abc def ghi quoted asterisk abc def ghi unquoted at abc def ghi quoted at abc def ghi IFS is now X unquoted asterisk abc def ghi quoted asterisk abcXdefXghi unquoted at abc def ghi quoted at abc def ghi
请注意，在IFS更改为“X”后，（仅）“引号星号”行显示每个“单词”之间的X. 如果IFS的值包含多个字符，则只有第一个字符用于此目的。
该功能也可以用于其他阵列：
$ array=(123 456 789) $ saveIFS=$IFS; IFS="|" $ echo "${array[*]}" 123|456|789 $ IFS=$saveIFS
请参阅特殊参数下的bash手册页。
Special Parameters The shell treats several parameters specially. These parameters may only be referenced; assignment to them is not allowed. * Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, it expands to a sin‐ gle word with the value of each parameter separated by the first character of the IFS special variable. That is, "$*" is equiva‐ lent to "$1c$2c...", where c is the first character of the value of the IFS variable. If IFS is unset, the parameters are sepa‐ rated by spaces. If IFS is null, the parameters are joined without intervening separators. @ Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is, "$@" is equivalent to "$1" "$2" ... If the double-quoted expansion occurs within a word, the expansion of the first parameter is joined with the begin‐ ning part of the original word, and the expansion of the last parameter is joined with the last part of the original word. When there are no positional parameters, "$@" and $@ expand to nothing (ie, they are removed).
使用"$@"而不是$*更安全。 当您使用多字字符串作为shell脚本的参数时，只有"$@"将每个引用的参数解释为单独的参数。
如上面的输出所示，如果使用$* ，那么shell会对参数进行错误计数。
for i in "$@" do echo $i # loop $# times done for i in "$*" do echo $i # loop 1 times done