Question

I don’t how to use regex properly in bash, i got an error trying to do in this way, what is wrong in that regex verification?

#!/bin/bash

if [ ! $# -eq 1 ]; then
        echo "Error: wrong parameters"
else
        if [ $1 =~ "[a-z]" ]; then
                echo "$1: word"
        elif [ $1 =~ "[0-9]" ]; then
                echo "$1: number"
        else
                echo "$1: invalid parameter"
        fi
fi

Answer 1

I have reworked your script and get the expected result with the following:

  #!/bin/bash                                                                                                                                                                                      
  if [ ! $# -eq 1 ]; then
    echo "Error: wrong parameters"
  else
    if [[ $1 =~ ^[a-z]+$ ]]; then
      echo "$1: word"
    elif [[ $1 =~ ^[0-9]+$ ]]; then
      echo "$1: number"
    else
      echo "$1: invalid parameter"
    fi
  fi

You do not need to quote your Regex.