Frank, I don’t know if this is related, but I have found that I always have to enter this command after logging into the POSIX /bin/sh on z/OS via regular telnet (not SSH):
stty erase ^? In other words, erase (backspace in stty terms) is Cntl-? instead of Cntl-H. HTH Peter From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Frank Swarbrick Sent: Wednesday, April 9, 2025 6:08 PM To: [email protected] Subject: Issue with z/OS pseudo-terminal programming I am implementing z/OS support for the "micro" TUI editor, which is written in Go. The current source code, sans z/OS support, is here: https://urldefense.com/v3/__https://github.com/zyedidia/micro__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1OSiBFzFgQ$<https://urldefense.com/v3/__https:/github.com/zyedidia/micro__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1OSiBFzFgQ$> One feature of the editor is the ability to open a "terminal window". This feature makes use of a go PTY package, which is found here: https://urldefense.com/v3/__https://github.com/creack/pty__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1ORlILujNg$<https://urldefense.com/v3/__https:/github.com/creack/pty__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1ORlILujNg$> Partial support for z/OS was added to this package by (if I recall correctly) an intern on the Go for z/OS team. I had to add some additional code to get the Micro terminal window support to work (specifically, something to deal with EBCDIC newline to ASCII CRLF support), but that is not the issue that I am looking to resolve with this post. The z/OS execution of the test suite for the package fails on one particular test case. That test case deals with the backspace control character. After figuring out how the results on z/OS differ from the expected results I have created a C language project (just one program) that demonstrates the issue. I did this so that it is demonstrated that the same issue is present within just the C runtime, and is not specific to the Go runtime. This package is here: https://urldefense.com/v3/__https://github.com/fswarbrick/xpty__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1ORFgPk6qA$<https://urldefense.com/v3/__https:/github.com/fswarbrick/xpty__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1ORFgPk6qA$> The README.MD file in this package goes in to detail about the issue. But the crux of it is that z/OS pseudo-terminal support appears to behave in a manner a bit differently than (all other?) POSIX environments. My specific tests were on z/OS and Linux (for x86/64). Below are the outputs from my test program, xpty.c. I'm not sure how the backspace control character will present itself within this post, so I have also displayed the hex values of the results. Linux results: Pty write bytes 7: 01293 30 31 32 39 8 33 a -------------------------------- Pty read result: 7: 01293 30 31 32 39 8 33 a -------------------------------- Tty read result: 9: 0129^H3 30 31 32 39 5e 48 33 d a -------------------------------- Z/OS results: MVS master Terminal /dev/ptyp0008 3 819 0 Terminal /dev/ptyp0008 3 819 1047 slave Terminal /dev/ttyp0008 4 819 0 Terminal /dev/ttyp0008 4 819 1047 Pty write bytes 7: 01293 30 31 32 39 8 33 a -------------------------------- Pty read result: 5: 0123 30 31 32 33 a -------------------------------- Tty read result: 9: 0129 3 30 31 32 39 8 20 8 33 a -------------------------------- The result files (zos_results.txt and linux_results.txt) are also part of my xpty package on github. If you are interested in helping me resolve this issue, please take a look at this package (again, that's https://urldefense.com/v3/__https://github.com/fswarbrick/xpty__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1ORFgPk6qA$<https://urldefense.com/v3/__https:/github.com/fswarbrick/xpty__;!!Ebr-cpPeAnfNniQ8HSAI-g_K5b7VKg!JVb1Eoy1pjNCjBpOQ7S6SJe3V42ErNteZiSZWqmH-Zo8C7vkDbhVmHTI6sMQZ5qC84PnWmvXA5ms5uLl5m8-lNF_1ORFgPk6qA$>). You can reply to this post, or you can enter the "Discussion" area in my xpty repository and respond there. Thanks in advance! Frank This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. 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