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

这是我整理的东西:

#!/bin/sh

promptyn () {
    while true; do
        read -p "$1 " yn
        case $yn in
            [Yy]* ) return 0;;
            [Nn]* ) return 1;;
            * ) echo "Please answer yes or no.";;
        esac
    done
}

if promptyn "is the sky blue?"; then
    echo "yes"
else
    echo "no"
fi

我是一个初学者,所以要谨慎对待,但它似乎奏效了。

其他回答

受到@Mark和@Myrdin的回答的启发,我创建了一个通用提示的函数

uniprompt(){
    while true; do
        echo -e "$1\c"
        read opt
        array=($2)
        case "${array[@]}" in  *"$opt"*) eval "$3=$opt";return 0;; esac
        echo -e "$opt is not a correct value\n"
    done
}

这样使用:

unipromtp "Select an option: (a)-Do one (x)->Do two (f)->Do three : " "a x f" selection
echo "$selection"

使用read命令:

echo Would you like to install? "(Y or N)"

read x

# now check if $x is "y"
if [ "$x" = "y" ]; then
    # do something here!
fi

然后你需要的所有其他东西

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
}

您可以编写一个函数来测试:

confirm() {
  local ans IFS=;
  while read -rp "$1" -n1 ans;
  do printf '\n';
    case $ans in [Yy]) return 0;;
      [Nn]) return 1;;
    esac;
  done;
}; ## Usage: if confirm "Are you sure? "; then ...

if confirm "Does everything look ok...reboot now? [Y/n]"; then
  echo "rebooting..."
  sleep 5
  reboot
fi
echo "Please enter some input: "
read input_variable
echo "You entered: $input_variable"