When you run

test="-efoo"; echo ${test:0:2}

echo is run with the argument -e, which is a valid option and is thus “swallowed”.

Use printf instead:

test="-efoo"; printf %s\\n ${test:0:2}

When you run

test="-efoo"; echo ${test:0:2}

echo is run with the argument -e, which in some echo implementations including the echo builtin command of most bash deployments, is a valid option and is thus “swallowed”.

Use printf instead:

test="-efoo"; printf %s\\n "${test:0:2}"

When you run

test="-efoo"; echo ${test:0:2}

echo is run with the argument -e, which is a valid option and is thus “swallowed”.

Use printf instead:

test="-efoo"; printf %s\\n ${test:0:2}

When you run

test="-efoo"; echo ${test:0:2}

echo is run with the argument -e, which is a valid option and is thus “swallowed”.

Use printf instead:

test="-efoo"; printf %s\\n ${test:0:2}