Both the inclusion of new lines in a work file by means of EDT statements (e.g. by reading a file or copying lines etc.) and the deletion of lines if the previous last line in the work file is one of the deleted lines usually result in a modification to the current line number (there are a few exceptions where the current line number remains unchanged). The new current line number is usually determined from the line number of the last line in the work file plus the current increment. However, in some cases, the current line number is the line number of the last line inserted by the EDT statement plus the current increment.
The numbering of lines which are newly inserted in a work file is performed using one of the five procedures listed below.