You can use tStatCatcher component to catch all the execution log details and then save these logs to a file using tFileOutputDelimited component.
tLog4j component should be used along with tInitLog4j to log in txt files.
Its free and can be downloaded from https://exchange.talend.com/
What's kind of execution log do you want to log to file?
It is very convenient to set the log in job view to output the record into a file or table.
Statistics table records details like begin Time, End Time which is generated by any job.
Logs table records the messages from Java Exception, tDie and/or tWarn (prerequisite: there must be an error in your job).
Flow Meter table records the number of rows processed in the defined flow(prerequisite: you have to use tFlowMeter in your job).
Let us know if it is Ok with you.
Could you please take a look at my screenshot to see if it is what you are looking for?