# string match -r "[" "a[sd"
string match: Regular expression compile error: missing terminating ] for character class
string match: [
string match: ^

# string invalidarg
string: Subcommand 'invalidarg' is not valid
Standard input (line 251): 
string invalidarg; and echo "unexpected exit 0" >&2
^

# string repeat -n-1 "foo"
string repeat: Invalid count value '-1'

# string repeat -m-1 "foo"
string repeat: Invalid max value '-1'

# string repeat -n notanumber "foo"
string repeat: Argument 'notanumber' is not a number

# string repeat -m notanumber "foo"
string repeat: Argument 'notanumber' is not a number

# echo "stdin" | string repeat -n1 "and arg"
string repeat: Too many arguments

# string repeat -n
string repeat: Expected argument

# string repeat -l fakearg 2>&1
string repeat: Unknown option '-l'
Standard input (line 352): 
string repeat -l fakearg
^