Entering the Zsh Debugger

Invoking the Debugger Initially

The simplest way to debug your program is to run zshdb. Give the name of your program and its options and any debugger options:

$ cat /etc/profile

if [ "${PS1-}" ]; then
    if [ "`id -u`" -eq 0 ]; then
      PS1='# '
    else
      PS1='$ '
    fi
  fi
fi

if [ -d /etc/profile.d ]; then
  for i in /etc/profile.d/*.sh; do
    if [ -r $i ]; then
      . $i
    fi
  done
  unset i
fi

$ zshdb /etc/profile

For help on zshdb or options, use the --help option.

$ zshdb --help

Usage:
   zshdb [OPTIONS] <script_file>

Runs zsh <script_file> under a debugger.

options:
...

Calling the debugger from your program

Sometimes it is not feasible to invoke the program from the debugger. Although the debugger tries to set things up to make it look like your program is called, sometimes the differences matter. Also the debugger adds overhead and slows down your program.

Another possibility then is to add statements into your program to call the debugger at the spot in the program you want. To do this, you source zshdb/dbg-trace.sh from where wherever it appears on your filesystem. This needs to be done only once.

After that you call _Dbg_debugger.

Here is an Example:

source path-to-zshdb/zshdb/dbg-trace.sh
# work, work, work.
# ... some zsh code

_Dbg_debugger
# start debugging here

Since _Dbg_debugger a function call, it can be nested inside some sort of conditional statement allowing one to be very precise about the conditions you want to debug under. And until first call to _Dbg_debugger, there is no debugger overhead.

Note that _Dbg_debugger causes the statement after the call to be stopped at.