Debugging

Verbose Logging

The --log-verbose flag logs script comments and command executions to stderr:

lash script.lash --log-verbose

Event	Format
Comment	[debug] # comment text
Pipeline	[exec] program args | program args

Pipeline commands are logged after variable expansion, so you see the actual values passed to each command.

Variable Tracing

The --log-variables flag logs variable mutations to stderr. An optional comma-separated name filter limits output to specific variables:

lash script.lash --log-variables          # all variable changes
lash script.lash --log-variables x,y      # only x and y

Event	Format
Declaration	[var] let name = value
Assignment	[var] name = value
Drop	[var] drop name

Combining Flags

Flags can be combined. All debug output goes to stderr, so it doesn’t interfere with script output:

lash script.lash --log-verbose --log-variables x,count

With Unit Tests

Combine with --test to see test names printed before execution:

lash script.lash --test --log-verbose

Each unittest block’s preceding comment is printed as [debug] # comment text before the test runs.

Debug Adapter Protocol

For interactive debugging with breakpoints and variable inspection, see Debug Adapter (DAP).