A transferred file is unreadable

Almost always character encoding

Traditional z/OS data is EBCDIC; files from other platforms are usually ASCII or UTF-8. Whether a tool converts depends on the file's tag and the transfer mode used.

Diagnose

1. ls -T on the Unix file — is it tagged, and as what?
2. Was the transfer done in text or binary mode? Text converts; binary does not.
3. View the file with HEX ON. EBCDIC spaces are x'40'; ASCII spaces are x'20'. Digits are F0–F9 in EBCDIC, 30–39 in ASCII.
4. Check for stray carriage returns (x'0D') from a Windows source.

Fix

• Tag the file correctly with chtag so tools handle it consistently.
• Convert deliberately with iconv rather than relying on a transfer mode.
• Decide once, per interface, whether files arrive as ASCII or EBCDIC, and document it.