How to update commands in Ola Hallengren's SQL Server jobs?
You can update steps without completely recreating everything and without pointing and clicking yourself to death in the UI. You can just write manual queries directly against msdb.dbo.sysjobsteps (start with SELECTs that issue the REPLACE() calls, then when you're happy, change it to UPDATE).

SELECT REPLACE(js.command, N'foo', N'bar') 
  FROM msdb.dbo.sysjobsteps AS js
  INNER JOIN msdb.dbo.sysjobs AS j
  ON js.job_id = j.job_id
  WHERE j.name = N'name of the job';


When you're satisfied it's correct, only the first couple of lines change:

UPDATE js
  SET command = REPLACE(js.command, N'foo', N'bar') 
  FROM msdb.dbo.sysjobsteps AS js
  INNER JOIN msdb.dbo.sysjobs AS j
  ON js.job_id = j.job_id
  WHERE j.name = N'name of the job';


It's tough to get more automated than that (e.g. update more than one job at once), since the string you want to replace might not be exactly the same in all job steps, and you might get false positives, too.