循环内的bash多个if语句不起作用

Question

I am new to bash scripting, I have a file and i want to check each line but it is not working.

My bach script code

declare -a arr

for (( i=0; i<${len}; i++ ))
do
    if [[ ${arr[$i]} =~ ^[0-9]+$ ]]
    then
      echo ${arr[$i]}" numbr"
    
    else
        echo "No match"
     fi
done

Why only last line is match ? is there any space or line break issue ? suggest me some solution

Answer 1

Your file is saved in "DOS" format, with \\r\\n line endings.

To convert to "unix" format:

dos2unix file.txt
# or, if that's not installed
sed -i 's/\r$//' file.txt

---

tangentially, I find the POSIX character class can describe what you want to match:

[[ ${arr[$i]} =~ ^[[:digit:]]+$ ]] && echo "${arr[i]} numbr"
[[ ${arr[$i]} =~ ^[[:alpha:]]+$ ]] && echo "${arr[i]} ltr only"
[[ ${arr[$i]} =~ ^[[:alnum:]]+$ ]] && echo "${arr[i]} both"

Answer 2

Your issue is MS-DOS line endings of $'\\r\\n' instead of $'\\n' only.

You can remove the offending $'\\n' on-the-fly like this:

mapfile -t arr < <(tr -d '\r' <file.txt)

Other than that, I suggest you check you script with https://shellcheck.net/ as it has some issues