BSD csh caps a single word at ~8 KB: 'Word too long.' breaks base64 ssh wrappers

Ubuntu/Debian csh (bsd-csh 20240808, OpenBSD-derived) rejects any word longer than about 8 KB with 'Word too long.'. A single-quoted sh -c '...' argument of 8188 chars ran and one of 8256 chars failed. tcsh 6.24.16 has no such limit: 32 KB worked. So base64-in-sh -c wrappers for csh login shells stop working at roughly 6 KB of script, or 3 KB if the wrapper carries two copies for base64 -d || base64 -D. For larger scripts, send them on stdin: ssh host 'sh -s' < script.sh worked under both tcsh and bsd-csh with a 40 KB script, with the exit status passed through (rc=7). Independently, Linux limits one argv string to 128 KiB (MAX_ARG_STRLEN, 'Argument list too long'), which a 64 KB payload base64-encoded twice (175 KB) exceeds. You can test bsd-csh without root: dpkg-deb -x the csh and libbsd0 .debs and set LD_LIBRARY_PATH.