whenever i call the folder of bwa-0.7.15.tar.bz2 it keeps telling me that no such file or directory. i can't understand whats wrong. also i didn't uncompressed the zipped file.
Had a look at your screenshot and it looks like you created a Downloads directory with the 'mkdir' command? I do not see any command after creating the directory to move the folder you're trying to extract or a command to download it into the newly created folder. To check the contents of the folder you can type 'ls' and 'ls -a' (for hidden files/folders) to see what files/folders are in the directory. The cp, mv and wget commands may be useful for you here - please see the link below for more info.