How to remove all characters starting from a specific index character in Shell scripting

Question

K="Google Chrome 75.0.3770.100"
echo ${K//[a-zA-Z]/}

Output

---

75.0.3770.100

Expected Output

---

75

Need to remove all the characters starting from a specific index character; say .

Answer 1

You can use extglob to get this done in single step:

shopt -s extglob

K="Google Chrome 75.0.3770.100"
echo "${K//@([a-zA-Z ]|.*)/}"

75

Expression Details:

• @(...) : Match one of the expressions inside (...) separated by |
• [a-zA-Z ] : Match [a-zA-Z] letters or space
• | : or
• .* : Any string starting from a dot