import sys
#   Read a file specified by the first command line argument.
#   Print the number of characters in the file and then the file itself.

if len(sys.argv) < 2:
    print("Usage: infile_4.py <filename>")
    sys.exit(1) # Exit with an error code

filename = sys.argv[1]

try:
    with open(filename, mode="r") as f:
        for i,line in enumerate(f,1):
            print(f"[{i}]: {line}", end='')
except FileNotFoundError:
    print(f"The file {filename} cannot be found.")
    sys.exit(1)
except Exception as e:
    print(f"An error occurred: {e}")