我想暂停shell脚本中的输入,并提示用户进行选择。标准的是、否或取消类型问题。如何在典型的bash提示符中完成此操作?
当前回答
yn() {
if [[ 'y' == `read -s -n 1 -p "[y/n]: " Y; echo $Y` ]];
then eval $1;
else eval $2;
fi }
yn 'echo yes' 'echo no'
yn 'echo absent no function works too!'
其他回答
一个衬垫:
read -p "Continue? [Enter] → Yes, [Ctrl]+[C] → No."
这假设“否”和“取消”具有相同的结果,因此没有理由区别对待它们。
多选版本:
ask () { # $1=question $2=options
# set REPLY
# options: x=..|y=..
while $(true); do
printf '%s [%s] ' "$1" "$2"
stty cbreak
REPLY=$(dd if=/dev/tty bs=1 count=1 2> /dev/null)
stty -cbreak
test "$REPLY" != "$(printf '\n')" && printf '\n'
(
IFS='|'
for o in $2; do
if [ "$REPLY" = "${o%%=*}" ]; then
printf '\n'
break
fi
done
) | grep ^ > /dev/null && return
done
}
例子:
$ ask 'continue?' 'y=yes|n=no|m=maybe'
continue? [y=yes|n=no|m=maybe] g
continue? [y=yes|n=no|m=maybe] k
continue? [y=yes|n=no|m=maybe] y
$
它会将REPLY设置为y(在脚本中)。
仅单个按键
这里有一个更长但可重复使用的模块化方法:
返回0=yes和1=no无需按enter键-仅需一个字符可以按enter键接受默认选择可以禁用默认选项以强制选择适用于zsh和bash。
按enter键时默认为“否”
请注意,N是大写的。此处按enter键,接受默认值:
$ confirm "Show dangerous command" && echo "rm *"
Show dangerous command [y/N]?
还要注意,[y/N]?已自动追加。默认的“no”被接受,因此不会有任何回音。
重新提示,直到给出有效响应:
$ confirm "Show dangerous command" && echo "rm *"
Show dangerous command [y/N]? X
Show dangerous command [y/N]? y
rm *
按回车键时默认为“是”
请注意,Y是大写的:
$ confirm_yes "Show dangerous command" && echo "rm *"
Show dangerous command [Y/n]?
rm *
上面,我刚刚按了回车键,所以命令运行了。
输入时无默认值-需要y或n
$ get_yes_keypress "Here you cannot press enter. Do you like this [y/n]? "
Here you cannot press enter. Do you like this [y/n]? k
Here you cannot press enter. Do you like this [y/n]?
Here you cannot press enter. Do you like this [y/n]? n
$ echo $?
1
这里,返回了1或false。请注意,使用此较低级别的函数,您需要提供自己的[y/n]?促使
Code
# Read a single char from /dev/tty, prompting with "$*"
# Note: pressing enter will return a null string. Perhaps a version terminated with X and then remove it in caller?
# See https://unix.stackexchange.com/a/367880/143394 for dealing with multi-byte, etc.
function get_keypress {
local REPLY IFS=
>/dev/tty printf '%s' "$*"
[[ $ZSH_VERSION ]] && read -rk1 # Use -u0 to read from STDIN
# See https://unix.stackexchange.com/q/383197/143394 regarding '\n' -> ''
[[ $BASH_VERSION ]] && </dev/tty read -rn1
printf '%s' "$REPLY"
}
# Get a y/n from the user, return yes=0, no=1 enter=$2
# Prompt using $1.
# If set, return $2 on pressing enter, useful for cancel or defualting
function get_yes_keypress {
local prompt="${1:-Are you sure [y/n]? }"
local enter_return=$2
local REPLY
# [[ ! $prompt ]] && prompt="[y/n]? "
while REPLY=$(get_keypress "$prompt"); do
[[ $REPLY ]] && printf '\n' # $REPLY blank if user presses enter
case "$REPLY" in
Y|y) return 0;;
N|n) return 1;;
'') [[ $enter_return ]] && return "$enter_return"
esac
done
}
# Credit: http://unix.stackexchange.com/a/14444/143394
# Prompt to confirm, defaulting to NO on <enter>
# Usage: confirm "Dangerous. Are you sure?" && rm *
function confirm {
local prompt="${*:-Are you sure} [y/N]? "
get_yes_keypress "$prompt" 1
}
# Prompt to confirm, defaulting to YES on <enter>
function confirm_yes {
local prompt="${*:-Are you sure} [Y/n]? "
get_yes_keypress "$prompt" 0
}
您可以使用内置的read命令;使用-p选项向用户提示问题。
从BASH4开始,您现在可以使用-i建议答案:
read -e -p "Enter the path to the file: " -i "/usr/local/etc/" FILEPATH
echo $FILEPATH
(但请记住使用“readline”选项-e以允许使用箭头键进行行编辑)
如果你想要一个“是/否”的逻辑,你可以这样做:
read -e -p "
List the content of your home dir ? [Y/n] " YN
[[ $YN == "y" || $YN == "Y" || $YN == "" ]] && ls -la ~/
针对其他人:
您不需要在BASH4中指定大小写,只需使用',,'使var小写即可。此外,我强烈不喜欢将代码放在读取块内,获取结果并在读取块IMO外处理它。还包括一个“q”表示退出IMO。最后,为什么键入“yes”只需使用-n1并按y。
示例:用户可以按y/n和q退出。
ans=''
while true; do
read -p "So is MikeQ the greatest or what (y/n/q) ?" -n1 ans
case ${ans,,} in
y|n|q) break;;
*) echo "Answer y for yes / n for no or q for quit.";;
esac
done
echo -e "\nAnswer = $ans"
if [[ "${ans,,}" == "q" ]] ; then
echo "OK Quitting, we will assume that he is"
exit 0
fi
if [[ "${ans,,}" == "y" ]] ; then
echo "MikeQ is the greatest!!"
else
echo "No? MikeQ is not the greatest?"
fi