Hi Gustavo, There are two ways: 1- RECALL_COMMANDS function returns a string array containing the entries in IDL’s command recall buffer. 2- Go to the following hidden directory (under Windows for example) where you will find the file "history": C:\Documents and Settings\\.idl\idl\rbuf\ where is your user name. I hope this helps!. Cheers. Fernando Exelis VIS

Hi, I know this is an old thread, but I have the same problem (often) as the original poster and the suggested solution does not address the problem.
When Windows reboots with the IDL Workbench still active, ALL commands issued at the workbench console since the last startup are lost. They ARE NOT saved in the recall command buffer. This is a very annoying and costly problem with the Workbench, which seems to only flush the recall buffer to the history file when gracefully exiting the Workbench.
Is there a Workbench setting or method to force a recall buffer write to permanent storage each time a command is entered?
Thanks for any help.

Unfortunately there isn't a way to force the command history into the default IDL history file on demand. It only saves the current command history buffer when IDL closes gracefully.

However, you can use the RECALL_COMMANDS function to manually save the contents of the session's active command buffer to a (separate) file. You could create a custom routine procedure that can be called anytime you want to export your command buffer. Something like this:

PRO exportCommandHistory
fName = 'command_history.txt'
openw,unit,fName,/GET_LUN
printf,unit,RECALL_COMMANDS()
free_lun,unit
print, 'Command History Saved to File: '+fName
END

If you want to automate this saving of the buffer, you could set it up inside an asynchronous TIMER block: https://www.nv5geospatialsoftware.com/docs/TIMER.html

Something like this:

PRO exportCommandHistory, id,userData
fName = 'command_history.txt'
openw,unit,fName,/GET_LUN
printf,unit,RECALL_COMMANDS()
free_lun,unit
print, 'Command History Saved to File: '+fName
END

id = Timer.Set(300, 'exportCommandHistory',/REPEAT) ;command history exported to file every 5 minutes (300 sec)

If you want the history saving timer to be running in the background every time you launch IDL, you may consider adding it to your IDL startup script, which I think should work but I haven't tested that.

Finally, instead of writing to a custom output file, you could instead write to IDL's default history file (~\.idl\idl\rbuf\history). This has not been tested and could possibly corrupt your history file. Use with caution.