What can I use to edit program source in Unix Services on z/OS?

I hit this question trying to edit some Python programs on z/OS in Unix Services.

ISPF services

The easy answer for programs which are in EBCDIC or untagged, is just use ISPF edit, and you can use the HILITE command to highlight the constants and variables in the file. You can use this command to highlite, C, REXX, JCL, XML, assembler etc.

Example output for a C program.

Unfortunately although python supports EBCDIC source files, if you want to compile and package these files, they need to be ASCII files. The Unix Services command OEDIT will detect that the file as an ASCII file, and you can edit it, but not use the HILITE command.

To display the type of the file, use the Unix command ls -Tr *.py . This gave me

t ISO8859-1   T=on  cf.py        
- untagged    T=off aa.py        

Where cf.py is tagged as an ASCII file, an aa.py is an untagged file which defaults to EBCDIC.

Download to your work station

You can download ( FTP) these files to your work station, in binary and edit them. I use gedit on Linux. This has support built in for highlighting source.

IBM developer for z/OS.

This is an eclipse based package which allows you to edit data sets, submit jobs, debug programs etc. It has build in support for C, COBOL etc. When you right click on a file, you can select which editor to use, for example LPEX, a simple editor,a remote C/C++ editor, or an editor on your work station (gedit in my case).

For a python file (*.py), Eclipse downloads the file, and the choice is the eclipse simple text editor, or your workstation standard editor (gedit).


Pydev is an Integrate Development Environment for Python on Eclipse (IBM Developer for z/OS). I had a few problems getting it working in Eclipse. (I had to use Pydev 8.2 because of incompatible Java release problem). This provides a Python editor with highlighting, and support for “twisties” where you can hide functions etc. As an editor this worked fine for most of the things I did. There were a couple of surprises.

I could not get the debugger to work, as it tried to debug running the Python program on my laptop – not on z/OS.

Whoops who over wrote my file

With all of the non ISPF techniques there is an integrity problem. If there are two people A and B and they want to edit the file at the same time.
With ISPF and ISPF

  • A edits the file
  • B is prevented from editing the file
  • A saves the updates

If A uses ISPF and B uses IBM developer

  • A edits the file
  • B edits the file
  • A saves the file
  • When B tries to save the file, it detects the last changed time stamp is different, and asks if you want to overwrite it

If A uses ISPF and B uses IBM developer

  • A edits the file
  • B edits the file
  • B saves the file, and as the last changed time stamp has not changed, the save is successful
  • A saves the file, and overwrites the changes B made.

If you use FTP or similar to download the files, there is no locking, and the last person to save will overwrite any previous updates from other people.

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