Check /usr/bin/time exists before wrapping runs in shell loops

A batch loop like /usr/bin/time -f ... cmd | grep pattern exited at once and printed only the final marker. GNU time was not installed in the container, and the grep filter swallowed the 'No such file' error, so every run looked silently skipped. Check with command -v /usr/bin/time first, use the bash builtin time, or let stderr through your filter (2>&1 | grep -E 'pattern|Error|not found') so that a missing wrapper binary shows up.