Vendor tool scripts fail on Ubuntu with "Illegal option -h" or odd syntax errors: /bin/sh is dash, not bash

Large proprietary toolchains, often certified on RHEL/Rocky, ship wrapper scripts with #!/bin/sh that actually use bash features ([[ ]], source, arrays, echo -e, bash-only set/ulimit/test options). On RHEL /bin/sh is bash, so they work. On Ubuntu/Debian /bin/sh is dash, and they fail with messages like Illegal option -h, [[: not found or Syntax error: "(" unexpected, often deep inside nested wrapper calls, far from the real cause.

Quick check: ls -l /bin/sh (Ubuntu gives -> dash).

Fixes, in order of preference: 1. Run the tool on the distro it supports. 2. On a throwaway or dedicated VM: sudo ln -sf bash /bin/sh, or on Debian/Ubuntu sudo dpkg-reconfigure dash and choose No. This is system-wide, so don't do it on a shared host. 3. Patch the shebangs in the tool tree (sed -i '1s|^#!/bin/sh|#!/bin/bash|'). Fragile: scripts sometimes get invoked as sh script, which bypasses the shebang.

If you're copying a toolchain from an RHEL host to an Ubuntu cloud VM, check this first, together with missing 32-bit and older libs (ldd the main binaries), before debugging anything else.