tasks a-s

Task/Remove-lines-from-a-file/PowerBASIC/remove-lines-from-a-file.powerbasic

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+#DIM ALL
+
+FUNCTION PBMAIN () AS LONG
+    DIM filespec AS STRING, linein AS STRING
+    DIM linecount AS LONG, L0 AS LONG, ok AS LONG
+
+    filespec = DIR$(COMMAND$(1))
+    WHILE LEN(filespec)
+        linecount = 0: ok = 0
+        OPEN filespec FOR INPUT AS 1
+        OPEN filespec & ".tmp" FOR OUTPUT AS 2
+        DO UNTIL EOF(1)
+            LINE INPUT #1, linein
+            INCR linecount
+            IF VAL(COMMAND$(2)) <> linecount THEN
+                PRINT #2, linein
+            ELSE
+                ok = -1
+                FOR L0 = 2 TO VAL(COMMAND$(3))
+                    IF EOF(1) THEN
+                        ok = 1
+                        PRINT "Tried to remove beyond the end of "; filespec
+                        EXIT DO
+                    END IF
+                    LINE INPUT #1, linein
+                NEXT
+            END IF
+        LOOP
+        IF 0 = ok THEN
+            PRINT "Lines to remove are beyond the end of "; filespec
+        ELSEIF -1 = ok THEN
+            PRINT filespec; ": done"
+        END IF
+        CLOSE
+        filespec = DIR$
+    WEND
+END FUNCTION