How to trim last part of the string having delimiter?

Question

I have string(s) having delimiter underscore(_)

Input -

1. ABC_TEST
2. PQR_XYZ_TEST
3. PQR_XYZ_ABC_TEST

Expected output -

1. ABC
2. PQR_XYZ
3. PQR_XYZ_ABC

I want to remove only last part of the string. Can anyone suggest quicker way probably one-liner to achieve this?

Answer 1

string='ABC_TEST'
mod_string="${string%_*}"
echo "$mod_string"
ABC

Answer 2

The basic sed command is:

sed 's/_TEST$//' filename

or, to remove anything after the last _:

sed 's/_[^_]*$//' filename

If the strings come from another command: command | sed ...

If it's a variable sed ... <<< "${VARIABLE}"