Type
   Person = Record
      FirstName: String[15];
      LastName : String[25];
      Address  : String[35];
   end;
   PersonFile = File of Person;
   NumberFile = File of Integer;
   SwapFile   = File;
Assign 

	
Assign(var f; name: string); 

	
Assigns the name of an external file to a file variable. 
Reset 

		
Reset(var f [: file; recsize: Word ] ); 

		
Opens an existing file. 
Rewrite 

		
Rewrite(var f: file [; recsize: Word ] ); 

		
Creates and opens a new file. 
Close 

		
Close(var f); 

		
Closes an open file. 
Append

	
Append(var f: text); 

	
Opens an existing file for appending (f is a text-file variable). 
Truncate 

		
Truncate(var f); 

		
Truncates the file at the current file position. 
Read

	
Read(f , v1 [, v2,...,vn ] );

	
For typed files, reads a file component into a variable.

		
Read( [ var f: text; ] v1 [, v2,...,vn ] );

		
For text files, reads one or more values into one or more variables.With a type string variable, Read reads all characters up to, but not including, the next end-of-line marker or until Eof(f) becomes True; it does not skip to the next line after reading.After the first Read, each subsequent Read will see the end-of-line markerand return a zero-length string.Use multiple Readln calls to read successive string values.
Write

		
Write(f, v1 [, v2,...,vn ] );

		
For typed files, writes a variable into a file component.

		
Write( [ var f: text; ] v1 [,v2,...,vn ] );

		
For text files, writes one or more values to the file.
ReadLn

		
ReadLn([ var f: text; ] v1 [, v2, ..., vn ] );

		
Executes the Read procedure, then skips to the next line of the file.After executing Read, Readln skips to the beginning of the next line of the file.
WriteLn

		
WriteLn([ var f: text; ] v1 [, v2, ..., vn ] );

		
Executes the Write procedure, then outputs an end-of-line marker to the file.
Eof

	
Eof(var f): Boolean;

	
Eof [ (var f: text) ]: Boolean;

	
Returns the end-of-file status.
Eoln

		
Eoln [(var f: text) ]: Boolean;

		
Returns the end-of-line status of a text file
FilePos

		
FilePos(var f): Longint;

		
Returns the current file position of a file.
FileSize

		
FileSize(var f): Longint;

		
Returns the current file position of a file.
Seek

		
Seek(var f; n: Longint);

		
Moves the current position of a file to a specified component.
Erase

	
Erase(var f);

	
Erases an external file.
Rename

		
Rename(var f; newname: string);

		
Renames an external file.