Defensive File Operations

Path Guard

Check a Target

File scripts should check that a target value exists before building a command plan. This keeps missing input from turning into a broad file operation.

Program

Play the script to choose the target and see the guarded action.

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

target=
if [ -n "$target" ]; then
    action="check:$target"
else
    action="skip:missing-target"
fi
echo "$action"

#!/usr/bin/env bash

target=
if [ -n "$target" ]; then
    action="check:$target"
else
    action="skip:missing-target"
fi
echo "$action"
guard A guard checks that input is safe before a file action is planned.
target The target names the file or directory the action will use.
empty value An empty target should skip the operation instead of expanding into a risky path.