Selective file copy

Selective file copy is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Copy part of input records to an output file.

Show how file processing as known from PL/I or COBOL can be implemented in the language of your choice.
Here, a file is not 'just' a sequence of bytes or lines but a sequence of recods (structured data). The structure is usually described by declarations contained in an INCLUDE file (PL/I) or COPY BOOK (COBOL).
The by name assignment is a little extra available in PL/I.
Data conversions may be necessary (as shown here for data element c.

Java

With a little help from my friens <lang java>import java.io.BufferedWriter; import java.io.FileWriter; import java.io.File; import java.io.IOException; import java.util.Scanner;

class CopysJ {

 public static void main(String[] args) {
   String ddname_IN  = "copys.in.txt";
   String ddname_OUT = "copys.out.txt";
   if (args.length >= 1) { ddname_IN  = args[0].length() > 0 ? args[0] : ddname_IN; }
   if (args.length >= 2) { ddname_OUT = args[1].length() > 0 ? args[1] : ddname_OUT; }

   File dd_IN = new File(ddname_IN);
   File dd_OUT = new File(ddname_OUT);

   try (
     Scanner scanner_IN = new Scanner(dd_IN);
     BufferedWriter writer_OUT = new BufferedWriter(new FileWriter(dd_OUT))
     ) {
     String a;
     String b;
     String c;
     String d;
     String c1;
     String x = "XXXXX";
     String data_IN;
     String data_OUT;
     int ib;

     while (scanner_IN.hasNextLine()) {
       data_IN = scanner_IN.nextLine();
       ib = 0;
       a = data_IN.substring(ib, ib += 5);
       b = data_IN.substring(ib, ib += 5);
       c = data_IN.substring(ib, ib += 4);
       c1=Integer.toHexString(new Byte((c.getBytes())[0]).intValue());
       if (c1.length()<2) { c1="0" + c1; }
       data_OUT = a + c1 + x;
       writer_OUT.write(data_OUT);
       writer_OUT.newLine();
       System.out.println(data_IN);
       System.out.println(data_OUT);
       System.out.println();
     }
   }
   catch (IOException ex) {
     ex.printStackTrace();
   }
   return;
 }

}</lang>

NetRexx

with a little help from a friend <lang netrexx>/* NetRexx */ -- nrc -keepasjava -savelog copys options replace format comments java crossref symbols nobinary

parse arg ddname_IN ddname_OUT . do

 if ddname_IN.length = 0 then ddname_IN = 'copys.in.txt'
 if ddname_OUT.length = 0 then ddname_OUT = 'copys.out.txt'

 dd_IN = File(ddname_IN)
 dd_OUT = File(ddname_OUT)
 scanner_IN = Scanner(dd_IN)
 writer_OUT = BufferedWriter(FileWriter(dd_OUT))

 x = 'XXXXX'
 loop while scanner_IN.hasNextLine()
   data_IN = scanner_IN.nextLine()
   parse data_IN a +5 . /* b */ +5 c +4 . /* d */
   cc=c.left(1).c2x
   data_OUT = a || cc.right(2,0) || x
   writer_OUT.write(data_OUT)
   writer_OUT.newLine()
   end

catch ex = IOException

 ex.printStackTrace()

finally

 do
   if scanner_IN \= null then scanner_IN.close()
   if writer_OUT \= null then writer_OUT.close()
 catch ex = IOException
   ex.printStackTrace()
 end

end</lang>

ooRexx

<lang oorexx>/* REXX */ infile ="in.txt" outfile="out.txt"

s1=.copys~new(infile,outfile) loop i=1 to 5

 s1~~input~~output

end s1~close -- close streams (files) 'type' outfile

class copys

attribute a

attribute b

attribute c

attribute d

method init -- constructor

 expose instream outstream
 parse arg infile, outfile
 instream =.stream~new(infile)~~open
 outstream=.stream~new(outfile)~~open("replace")

method input -- read an input line

 expose instream a b c d
 parse value instream~linein with a +5 b +5 c +5 d +5

method output -- write an output line

 expose outstream a c
 outstream~lineout(a || c~c2x~left(2)'XXXXX')

method close -- close files

 expose instream outstream
 instream~close
 outstream~close</lang>

Output:

AA   01XXXXX
AAA  02XXXXX
AAAA 03XXXXX
AAAAA04XXXXX
AAAAA05XXXXX

PL/I

<lang pli>*process source attributes xref or(!);

copys: Proc Options(Main);
Dcl 1 s1 unal,
     2 a Char(5),
     2 b Char(5),
     2 c Bin Fixed(31),
     2 d Char(5);
Dcl 1 s2,
     2 a Char(5),
     2 c Pic'99',
     2 x Char(5) Init('XXXXX');
Dcl o1  Record Output;   /* create a test file */
Dcl in  Record Input;
Dcl out Record Output;
Do i=1 To 5;
  s1.a=repeat('A',i);
  s1.b=repeat('B',i);
  s1.c=i;
  s1.d=repeat('D',i);
  Write File(o1) From(s1);
  End;
Close File(o1);

On Endfile(in) Goto eoj;
Do i=1 By 1;             /* copy parts of the test file    */
  Read File(in) Into(s1);
  s2=s1, by name;        /* only fields a and c are copied */
  Write File(out) From(s2);
  End;
eoj:
End;

</lang>

Output:

AA   01XXXXX
AAA  02XXXXX
AAAA 03XXXXX
AAAAA04XXXXX
AAAAA05XXXXX

Rexx

Translation of: PL/I

<lang rexx>in='in.txt' out='out.txt'; 'erase' out Do While lines(in)>0

 l=linein(in)
 Parse Var l a +5 b +5 c +4 d +5
 chex=c2x(c)
 cpic=left(chex,2)
 call lineout out,a||cpic||'XXXXX'
 End

Call lineout in Call lineout out 'type' out</lang>

Output:

Using the test file produced by PL/I. The data conversion used for c is not very general!

AA   01XXXXX
AAA  02XXXXX
AAAA 03XXXXX
AAAAA04XXXXX
AAAAA05XXXXX