Question

我有一个shell脚本，需要向用户询问4行输入。然后我需要显示输入的最长行，然后整个输入必须进入文件。这就是我到目前为止所得到的：

#!/bin/bash
lines=()
echo  "Please enter 4 lines of text:  "
for ((i=1; i<=4; i++)); do
IFS= read -p ""  -r line && lines+=("$line")
done

echo "The longest line you entered was: "

max=0

for((i=0;i<4;i++)); do
len=${#lines}
if [[ len -gt max ]] ; then
max=$len
long="${lines}"
fi
done

echo longest line="${long}" length="${max}"

echo "I'm now putting the four lines you entered into a text file called \"mylines.txt\"..."
printf "%s\n" "${lines[@]}" > lines.txt

这不是发生在我身上，你能告诉我我做错了什么吗？感谢

Answer 1

你可以在第一个循环中找出最长的行和长度：

#!/bin/bash

lines=()
max=0   
echo  "Please enter 4 lines of text:  "

for ((i=1; i<=4; i++)); do
    IFS= read -r line
    lines+=("$line")
    [[ ${#line} -gt $max ]] && { max=${#line}; long="$line"; }
done

echo longest line="${long}" length="${max}"
echo "I'm now putting the four lines you entered into a text file called \"mylines.txt\"..."
printf "%s\n" "${lines[@]}" > lines.txt

Answer 2

使用您的确切示例，您只需要通过在设置len和long变量时指定索引$ i来实际遍历数组。

#!/bin/bash
lines=()
echo  "Please enter 4 lines of text:  "
for ((i=1; i<=4; i++)); do
IFS= read -p ""  -r line && lines+=("$line")
done

echo "The longest line you entered was: "

max=0

for((i=0;i<4;i++)); do
#See how I added the [$i] this will allow you to get the length of each item in the array
len=${#lines[$i]}
if [[ len -gt max ]] ; then
max=$len
#This gets the item in the array to set the value of $long to it.
long="${lines[$i]}"
fi
done

echo longest line="${long}" length="${max}"

echo "I'm now putting the four lines you entered into a text file called \"mylines.txt\"..."
printf "%s\n" "${lines[@]}" > lines.txt

输出：

Please enter 4 lines of text:  
one
two
three
four
The longest line you entered was: 
longest line=three length=5
I'm now putting the four lines you entered into a text file called "mylines.txt"...

如何显示用户输入的最长行

2 个答案: