A specific test on stage #MR9 fails because the characters $- are expanded to “Builtin Set Flags” on bash.
remote: [tester::#MR9] $ echo -n "×€÷_$-×" | ./your_program.sh -E "\w"
remote: [tester::#MR9] Expected exit code 0, got 1
remote: [tester::#MR9] Test failed (try setting 'debug: true' in your codecrafters.yml to see more details)
I believe the tests should use single quotes to avoid $ expansions. Using echo -n '×€÷_$-×' on my own machine worked, but echo -n "×€÷_$-×" was expanded to ×€÷_himBHs× and failed the test.