Python
# Program to search for a substring in a file
filename = input("Enter filename: ")
term = input("Enter search term: ")
try:
with open(filename, "r", encoding="utf-8") as f:
for line_no, line in enumerate(f, start=1):
if term in line:
print(f"Found on line {line_no}: {line.strip()}")
except FileNotFoundError:
print("File not found.")Output
Enter filename: notes.txt Enter search term: Python Found on line 3: Learning Python basics
Reads file line by line, checking membership of the substring and printing matching lines.