Anastasia Netz Anastasia Netz - 5 years ago 301
Bash Question

How to display the longest line from user input

I have a shell script that need to ask the user for 4 lines of input. Then I need to display the longest line that was entered, and then whole input is gotta go into the file.
That is what i got so far:

#!/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


This is not happening for me, can you tell me what am I doing wrong?
Thanks

Answer Source

You can figure out longest line and length in first for loop:

#!/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
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