Why doesn DCL symbol substitution work?
The DCL symbol substitution processing occurs only at the DCL prompt, not within data and not within files. If you wish to perform symbol substitution in this environment, you typically write a small file containing the command(s) and data to be invoked- potentially only the data-and you then invoke the created procedure or reference the specified data. In this case, use of a file containing nolinemode commands or other techniques might be useful-you will want to ensure that the text editor you use does not attempt to use screen mode or similar, as this is not generally considered adventageous within a command procedure. Tools such as FTP have alternatives: COPY/FTP. DCL symbol substitution occurs in two passes, using the ampersand and the apostrophe. In most cases, only the apostrophe is necessary. In a few cases-such as the DCL PIPE command-you will may need to use the ampersand to get the substitution to work. The following example uses ampersand substitution to transfer the content
