【BASH】如何从选项列表中选择

 

 

问题

如何提供给用户选项列表，并且只有在必要的时候，用户才需要进行选择

 

解决方案

使用bash内置的select命令来创建选项列表，用户通过对应的序号进行选择。

#!/bin/bash

# cookbook filename: select_dir
directorylist="Finished $(ls /)"
PS3='Directory to process? ' # Set a useful select prompt
until [ "$directory" == "Finished" ]; do
printf "%b" "/a/n/nSelect a directory to process:/n" >&2
select directory in $directorylist; do
# User types a number which is stored in $REPLY, but select
# returns the value of the entry
if [ "$directory" = "Finished" ]; then
echo "Finished processing directories."
break
elif [ -n "$directory" ]; then
echo "You chose number $REPLY, processing $direc"
# Do something here
break
else
echo "Invalid selection!"
fi
# end of handle user's selection
done # end of select a directory
done # end of while not finished

讨论

通过上面的示例可以看出，select使得创建一个选项列表更加简单，不过值得注意的一点是要提供一个退出或是完成的选项。

用户的选择序号保存在$REPLY中，选择的值保存在调用select时候你指定的变量中。