Debugging Scripts

Variable Probe

Split a Debug Value

A probe line prints the values a script is about to use. Parameter expansion can split a compact debug value into named parts.

Program

Play the script to choose a probe value and see the parsed fields.

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

probe=
name="${probe%%:*}"
count="${probe##*:}"
echo "probe:$name=$count"

#!/usr/bin/env bash

probe=
name="${probe%%:*}"
count="${probe##*:}"
echo "probe:$name=$count"
probe A probe is a temporary diagnostic line that exposes values during development.
prefix trim `${probe%%:*}` keeps the text before the first colon-shaped separator.
suffix trim `${probe##*:}` keeps the text after the last colon-shaped separator.