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
在这种情况下,我已经多次使用case语句,使用case语句是一种很好的方法。可以实现while循环,该循环模拟case块,利用布尔条件,以便更好地控制程序,并满足许多其他要求。在满足所有条件后,可以使用中断,将控制权传递回程序的主要部分。此外,为了满足其他条件,当然可以在控制结构中添加条件语句:case语句和可能的while循环。
使用案例陈述来满足您的请求的示例
#! /bin/sh
# For potential users of BSD, or other systems who do not
# have a bash binary located in /bin the script will be directed to
# a bourne-shell, e.g. /bin/sh
# NOTE: It would seem best for handling user entry errors or
# exceptions, to put the decision required by the input
# of the prompt in a case statement (case control structure),
echo Would you like us to perform the option: "(Y|N)"
read inPut
case $inPut in
# echoing a command encapsulated by
# backticks (``) executes the command
"Y") echo `Do something crazy`
;;
# depending on the scenario, execute the other option
# or leave as default
"N") echo `execute another option`
;;
esac
exit
其他回答
要获得像inputbox这样的漂亮ncurses,请使用如下命令对话框:
#!/bin/bash
if (dialog --title "Message" --yesno "Want to do something risky?" 6 25)
# message box will have the size 25x6 characters
then
echo "Let's do something risky"
# do something risky
else
echo "Let's stay boring"
fi
默认情况下,对话框包至少在SUSE Linux上安装。看起来像:
检查此项
read -p "Continue? (y/n): " confirm && [[ $confirm == [yY] || $confirm == [yY][eE][sS] ]] || exit 1
作为单行命令的朋友,我使用了以下命令:
while [ -z $prompt ]; do read -p "Continue (y/n)?" choice;case "$choice" in y|Y ) prompt=true; break;; n|N ) exit 0;; esac; done; prompt=;
以长格式编写,其工作原理如下:
while [ -z $prompt ];
do read -p "Continue (y/n)?" choice;
case "$choice" in
y|Y ) prompt=true; break;;
n|N ) exit 0;;
esac;
done;
prompt=;
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
}
read -p "Are you alright? (y/n) " RESP
if [ "$RESP" = "y" ]; then
echo "Glad to hear it"
else
echo "You need more bash programming"
fi
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