Hello @girish6   Your first EL statement would work as well once you correct the single quote marks around the Z.  Many outside text editors end up messing up the single quotes, so the NiFi EL ends up being incorrect when you copy/paste. NiFi's EL editor built in to the processor property text blocks can help identify when the EL format is wrong. In above you can see your NiFi EL statement as copied and pasted on line 3. You'll notice the color coding indicates an issue with the function's input parameters. Line 1 has the properly formatted version of that same NiFi EL statement. Be careful when using copy paste from some external editors. Thank you, Matt ... View more

Hello @girish6,   NiFi Expression language does have a function that will increment a number, but it does not reset back to zero (unless you restart NiFi) and is incremented globally across call calls to that function.     So while this function will give each FlowFile a unique filename per NiFi node, there is no guarantee that they will be sequential or will start at 0 for new source zip file you extract.  If this works for your use case the NiFi Expression language statement would look like this in the UpdateAttribute processor: If you are just looking for filename uniqueness, a better solution may be to instead append the FlowFile's uniquely assigned UUID to the filename instead as follows:   Tips:  1. There is an expression language guide in the embedded help of your NiFi installation found by clicking on the global menu icon in upper right corner. 2. Within a NiFi processor property that support NiFi EL you can display a list of functions with details by typing "${" (signifies start of an EL statement) and then hold "Control" while clicking space bar.  This also works if you are mid statement and type ":"then "control" + click spacebar. Examples: file-${   (then cntrl+spacebar) ${uuid:  (then cntrl+spacebar) Hope this helps, Matt ... View more