What is Wildcard? Provide the examples of MS-DOS external and internal command with their execution syntax.

A Wildcard is a special character used in command-line environments to substitute for one or more unspecified characters in search or file management operations.

• * (Asterisk): Matches zero or more characters.
• ? (Question mark): Matches exactly one character.

MS-DOS Internal Commands (Built into command.com):

1. DIR — Displays list of files and directories.
   • Syntax: DIR [drive:][path][filename] (Example: DIR *.TXT)
2. COPY — Copies files from one location to another.
   • Syntax: COPY [source] [destination] (Example: COPY doc.txt D:\backup\)

MS-DOS External Commands (Stored as separate executable files like .EXE or .COM):

1. FORMAT — Formats a disk for use with MS-DOS.
   • Syntax: FORMAT drive: (Example: FORMAT D: /FS:NTFS)
2. CHKDSK — Checks a disk and displays a status report.
   • Syntax: CHKDSK [drive:] [/F] [/R] (Example: CHKDSK C: /F)