Hello, I am currently working on a project where I have to create a routine in order to process 2500 spectra from a field spectrometer. The files provided come in a ASD binary format that ENVI can read. I can import the files, then export them to ascii files (2 columns: wavelength, measure) using the spectral library. However, as they are classed in different folders depending on the study area, I would like to process them in IDL directly. When I try to open them using openw, lun,"P003-WRS.002", /get_lun it works. However, I can not export them to ascii. I have tried several solutions, but none work. I tried a solution given by Ethan Gutmann on his website: IDL> spawn, 'portspec -a' + "P003-WRS.000"+''+$ > '../prairie3/'+"test" This returns: % Type conversion error: Unable to convert given STRING to Long. % Detected at: $MAIN$ % PRINTF: File is not open for output. Unit: 0, File: % Error occurred at: $MAIN$ % Execution halted at: $MAIN$ I get the same error when trying to use printf. Does anyone have an idea to help me get out of this tricky situation (I am relatively new to programming). Cheers,