//
//concat command
//
//This command is used to concatinate records appointed file to current file.
//

//Syntax. 
concat [filename]@[prjname];
//Argument is filename to concatinate to current file.

//Example 1
hand id name/
1 yosida
2 imaoka
3 nakai
4 zuzuki
6 mizuno
7 hayasi
8 imai
;

put class_names;

hand score id/ 
81	1
62	2
52	6
75	4
91	5
36	3
;

//Execute concatinate records of appointed file 'class_name' to current file.
//If both file have common variable name. this variable is concatinated.
//But no common variable name are generated as lacked value.
concat class_names;



? or _ are lacked value which is generated at no common variable name by concat


//To contrast merge command with concat command. Show output of merge.