end of day 5 week 1

week 1/day 5/exo4.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+users=("admin" "root1" "John_Doe" "Alice" "Bob42")
+
+badChar=false
+
+for username in "${users[@]}"; do
+
+    badChar=false
+
+    for ((i=0; i<${#username}; i++)); do
+        char="${username:i:1}"
+        if ! [[ "$char" =~ [A-Za-z] ]]; then
+            badChar=true
+            break
+        fi
+    done
+
+    firstChar="${username:0:1}"
+    validFirstLetter=false
+
+    if [[ "$firstChar" =~ [A-Za-z] ]]; then
+        validFirstLetter=true
+    fi
+
+    if ! $badChar && (( ${#username} <= 20 )) && $validFirstLetter; then
+        echo "The username $username is valid"
+    else
+        echo "The username $username is not valid"
+    fi
+
+done
+