Report errors:

 ! [rejected]master -> master (fetch first)
error: failed to push some refs to 'https://github.com/rtczza/IPC.git'

You want to upload the fork folder and the files in its directory to github.

Use commands:

1,git add fork/

2,git commit -m "add fork"

3,git remote add origin https://github.com/rtczza/IPC.git

4,git push -u origin master

In step 4, the error is reported as follows:

root@ubuntu:/home/chemi/neo/ken/git# ls
fork
root@ubuntu:/home/chemi/neo/ken/git# git add fork/
root@ubuntu:/home/chemi/neo/ken/git# git commit -m "add fork"
[master (root-commit) c23e5f9] add fork
 2 files changed, 63 insertions(+)
 create mode 100755 fork/test
 create mode 100644 fork/test.c
root@ubuntu:/home/chemi/neo/ken/git# git remote add origin https://github.com/rtczza/IPC.git
root@ubuntu:/home/chemi/neo/ken/git# git push -u origin master
Username for 'https://github.com': rtczza
Password for 'https://rtczza@github.com': 
To https://github.com/rtczza/IPC.git
 ! [rejected]master -> master (fetch first)
error: failed to push some refs to 'https://github.com/rtczza/IPC.git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.
root@ubuntu:/home/chemi/neo/ken/git# 

Solution:

First use the git pull origin master command, then git push.

As shown below

root@ubuntu:/home/chemi/neo/ken/git# git pull origin master
From https://github.com/rtczza/IPC
 * branchmaster -> FETCH_HEAD
Merge made by the 'recursive' strategy.
 01_fork | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 01_fork
root@ubuntu:/home/chemi/neo/ken/git# 
root@ubuntu:/home/chemi/neo/ken/git# 
root@ubuntu:/home/chemi/neo/ken/git# git push -u origin master
Username for 'https://github.com': rtczza
Password for 'https://rtczza@github.com': 
Counting objects: 8, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (6/6), done.
Writing objects: 100% (7/7), 3.78 KiB | 0 bytes/s, done.
Total 7 (delta 0), reused 0 (delta 0)
To https://github.com/rtczza/IPC.git
   e34c88d..f354fde  master -> master
Branch master set up to track remote branch master from origin.
root@ubuntu:/home/chemi/neo/ken/git#

Then you can see the uploaded file in github.