Debugging Scripts

Debug Flag

Choose Verbose Mode

Many shell scripts use a flag to decide whether to print normal output or extra diagnostic detail.

Program

Play the script to choose debug mode and see the planned diagnostic output.

debug_flag.sh 
#!/usr/bin/env bash

debug=
if [[ "$debug" -eq 1 ]]; then
    mode="verbose"
else
    mode="normal"
fi
echo "debug:$mode"

#!/usr/bin/env bash

debug=
if [[ "$debug" -eq 1 ]]; then
    mode="verbose"
else
    mode="normal"
fi
echo "debug:$mode"
debug flag A small numeric flag can switch a script between normal and verbose behavior.
diagnostic mode Verbose mode should reveal decisions without changing the real result.
branch The `if` statement copies the selected behavior into one output variable.