If you need to submit sequencing or array raw or processed files to the GEO database (or some other database) you will be asked to provide checksum for the files you are uploading. This is needed to be sure that the files are transmitted correctly since if there was an error in the transmission the transmitted files will give a different checksum than the one you provided.
Open terminal. Type md5 followed by the name of the file
e.g. md5 assemblies.txt
you will get an output like this: MD5 (assemblies.txt) = c70fe79c7688ca69742c5ba4e11c3de0
Copy the code.