How to configure the fortran environment in linux

Linux programming and kernel information-general Linux technology-about how to configure the fortran environment in Linux. I am a beginner of linux, and I just got started with fortran. I cannot solve any small problem. Thank you for your help.
The downloaded intel linux compiler for linux 10 has been installed. Modify. bash_file according to some instructions on the Internet as follows:
#. Bash_profile

# Get the aliases and functions
If [-f ~ /. Bashrc]; then
.~ /. Bashrc
Fi

# User specific environment and startup programs

PATH = $ PATH: $ HOME/bin



Export PATH
Unset USERNAME
./Opt/intel/fc/10.0.023/bin/ifortvars. sh

Add "./opt/.../ifortvars. sh" to the last line"

Save and exit and execute the source. bash_profile command.

Next, when debugging the "hello world" program, the client fails to say that the permission is not enough, as shown below:
[Xdy @ localhost ~] $ Vi. bash_profile
[Xdy @ localhost ~] $ Source. bash_profile
[Xdy @ localhost ~] $ Cd/D/linuxlearning
[Xdy @ localhost linuxlearning] $ ifort first. f90
Ld: cannot open output file a. out: insufficient Permissions

I hope everyone will help me to see what went wrong? I am a beginner and I am not very clear about some concepts.