auto_resume ¶This variable controls how the shell interacts with the user and
job control.
If this variable exists then simple commands
consisting of only a single word,
without redirections, are treated as candidates for resumption
of an existing job.
There is no ambiguity allowed; if there is more than one job
beginning with or containing the word, then
this selects the most recently accessed job.
The name of a stopped job, in this context, is the command line
used to start it, as displayed by jobs.
If this variable is set to the value ‘exact’,
the word must match the name of a stopped job exactly;
if set to ‘substring’,
the word needs to match a substring of the name of a stopped job.
The ‘substring’ value provides functionality
analogous to the ‘%?string’ job ID (see Job Control Basics).
If set to any other value (e.g., ‘prefix’),
the word must be a prefix of a stopped job’s name;
this provides functionality analogous to the ‘%string’ job ID.