chtag does not work on z/OS UNIX

Question

I'm trying to tag ASCII files on z/OS host shell, so we do not have to specify the code page on the command line.

> echo > iso.txt
> chtag -t -c 819 iso.txt
> vi iso.txt

Type in "Hello" then quit and save

> ls -T iso.txt
t ISO8859-1   T=on  iso.txt
> od -x iso.txt
0000000000      C885    9393    9615

examining the iso.txt file shows it contains EBCDIC.

How do I set the tools to make use of the code page tag attribute? Note that explicitly specifying the code page using -W filecodeset=819 works.

Answer 1

There are support mechanisms for doing auto conversion based on tagging. To do what you’re interested in, I replicated your scenario on my z/OS 2.3 system. To accomplish what you want you can set _BPXK_AUTOCVT=ON. I repeated the provided test case and then set _BPXK_AUTOCVT=ON to demonstrate the desired behaviour worked.

$ echo > iso.txt
$ chtag -t -c 819 iso.txt
$ ls -T iso.txt
t ISO8859-1   T=on  iso.txt
$ vi iso.txt  (enter Hello, save then exit)
$ od -x iso.txt
0000000000      C885    9393    9615
0000000006

The word Hello is stored as EBCDIC despite having tagged the file as 819.
Next, setting _BPXK_AUTOCVT=ON enables auto conversion.

$ export _BPXK_AUTOCVT=ON
$ echo > iso.txt
$ chtag -t -c 819 iso.txt
$ vi iso.txt  (enter Hello, save then exit)
$ od -X iso.txt
0000000000          48656C6C        6F0A0000
0000000006

Here you can see that the auto-conversion function stored the text in the correct codeset.

References:

• IBM Doc on relevant Environment Variables
• File Tagging and Conversion