[ solved ] Extracting lines from a text file (CUPS error log)

[wedgetail]

I have an 8000 line plus file and would like to extract all lines containing recurring pattern, which can be almost anywhere in the lines.

As my brain is focused on the internals of CUPS and Ghostscript I don't seem to be able to get out of this mode in hurry. Bit of guidance to re-boot my brains  

For example I would like to extract all lines containing  [Job 3]  

[wedgetail]

TBercaht
Thank you just what I needed it was the \[ etc that caused me trouble, I just could not think, and it is getting worse. 

I have analysed thousands of lines from the cups error log. Seems to me that that pstops conversion is going weird, but the goalpost has just changed.  Anyway I should not report this here as I have just remembered ti is the KDE64-test05 I am running most of the time.