'$' 是什么意思？在 bash 脚本中是什么意思？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/10032078/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
What does '$?' mean in bash scripts?
提问by Meekohi
Possible Duplicate:
What does “$?” give us exactly in a shell script?
可能的重复：
什么是“$？” 给我们一个shell脚本？
What does $?mean in a bash script? Example below:
$?在 bash 脚本中是什么意思？下面的例子：
#!/bin/bash
# userlist.sh
PASSWORD_FILE=/etc/passwd
n=1 # User number
for name in $(awk 'BEGIN{FS=":"}{print }' < "$PASSWORD_FILE" )
do
echo "USER #$n = $name"
let "n += 1"
done
exit $?
回答by user unknown
$?
is the last error (or success) returned:
是返回的最后一个错误（或成功）：
$?
1: command not found.
echo $?
127
false
echo $?
1
true
echo $?
0
The exit in the end:
最后的出口：
exit $?
is superfluous, because the bash script will exit with that status anyway. Citing the man page:
是多余的，因为 bash 脚本无论如何都会以该状态退出。引用手册页：
Bash's exit status is the exit status of the last command executed in the script.
Bash 的退出状态是脚本中执行的最后一个命令的退出状态。
