Data commit

Task/Remove-lines-from-a-file/Icon/remove-lines-from-a-file.icon

@@ -0,0 +1,18 @@
+procedure main() # remove lines
+   removelines("foo.bar",3,2) | stop("Failed to remove lines.")
+end
+
+procedure removelines(fn,start,skip)
+
+   f := open(fn,"r") | fail                  # open to read
+   every put(F := [],|read(f))               # file to list
+   close(f)
+
+   if *F < start-1+skip then fail
+   every F[start - 1 + (1 to skip)] := &null # mark delete
+
+   f := open(fn,"w") | fail                  # open to rewrite
+   every write(\!F)                          # write non-nulls
+   close(f)
+   return                                    # done
+end