[kitten@wps85 ~]$ gitpull
bash: gitpull: command not found
[kitten@wps85 ~]$ git pull
fatal: Not a git repository (or any of the parent directories): .git
[kitten@wps85 ~]$ cd opt/
bash: cd: opt/: No such file or directory
[kitten@wps85 ~]$ cd /opt
[kitten@wps85 opt]$ git
usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path]
           [-p|--paginate|--no-pager] [--no-replace-objects]
           [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
           [--help] COMMAND [ARGS]

The most commonly used git commands are:
   add        Add file contents to the index
   bisect     Find by binary search the change that introduced a bug
   branch     List, create, or delete branches
   checkout   Checkout a branch or paths to the working tree
   clone      Clone a repository into a new directory
   commit     Record changes to the repository
   diff       Show changes between commits, commit and working tree, etc
   fetch      Download objects and refs from another repository
   grep       Print lines matching a pattern
   init       Create an empty git repository or reinitialize an existing one
   log        Show commit logs
   merge      Join two or more development histories together
   mv         Move or rename a file, a directory, or a symlink
   pull       Fetch from and merge with another repository or a local branch
   push       Update remote refs along with associated objects
   rebase     Forward-port local commits to the updated upstream head
   reset      Reset current HEAD to the specified state
   rm         Remove files from the working tree and from the index
   show       Show various types of objects
   status     Show the working tree status
   tag        Create, list, delete or verify a tag object signed with GPG

See 'git help COMMAND' for more information on a specific command.
[kitten@wps85 opt]$ git pull
fatal: Not a git repository (or any of the parent directories): .git
[kitten@wps85 opt]$ cd ~/.ssh
[kitten@wps85 .ssh]$ ls id_rsa id_rsa.pub known_hosts
id_rsa  id_rsa.pub  known_hosts
[kitten@wps85 .ssh]$ ssh-keygen -t rsa -C "dixian@cyber-village.net"
Generating public/private rsa key pair.
Enter file in which to save the key (/home/kitten/.ssh/id_rsa): /home/kitten/Desktop
/home/kitten/Desktop already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
open /home/kitten/Desktop failed: Is a directory.
Saving the key failed: /home/kitten/Desktop.
[kitten@wps85 .ssh]$ cd ~/.ssh
[kitten@wps85 .ssh]$ ls id_rsa id_rsa.pub known_hosts
id_rsa  id_rsa.pub  known_hosts
[kitten@wps85 .ssh]$ ssh-keygen -t rsa -C "dixian@cyber-village.net"
Generating public/private rsa key pair.
Enter file in which to save the key (/home/kitten/.ssh/id_rsa): /home/kitten/.ssh
/home/kitten/.ssh already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
open /home/kitten/.ssh failed: Is a directory.
Saving the key failed: /home/kitten/.ssh.
[kitten@wps85 .ssh]$ su
Password:
[root@wps85 .ssh]# cp /home/kitten/Desktop/c/* /home/kitten/.ssh/
cp: overwrite `/home/kitten/.ssh/id_rsa'?
cp: overwrite `/home/kitten/.ssh/id_rsa.pub'?
cp: overwrite `/home/kitten/.ssh/known_hosts'?
[root@wps85 .ssh]# ls -la
total 44
drwx------  2 kitten kitten 4096 Mar 10 10:18 .
drwxr-xr-x 57 kitten kitten 4096 Aug  2 12:38 ..
-rw-------  1 kitten kitten 1743 Jan  5  2016 cheeyung
-rw-r--r--  1 kitten kitten  400 Jan  5  2016 cheeyung.pub
-rw-------  1 kitten kitten 1743 Mar 10 10:17 id_rsa
-rw-r--r--  1 kitten kitten  407 Mar 10 10:17 id_rsa.pub
-rw-r--r--  1 kitten kitten 3952 Jan 28  2016 known_hosts
-rw-------  1 kitten kitten 1675 Dec 30  2015 kwangchin
-rw-r--r--  1 kitten kitten  400 Dec 30  2015 kwangchin.pub
-rw-------  1 kitten kitten 1671 Nov 17  2015 ta_gerrit_id_rsa
-rw-r--r--  1 kitten kitten  400 Nov 17  2015 ta_gerrit_id_rsa.pub
[root@wps85 .ssh]# cp /home/kitten/Desktop/c/* /home/kitten/.ssh/
cp: overwrite `/home/kitten/.ssh/id_rsa'? y
cp: overwrite `/home/kitten/.ssh/id_rsa.pub'? y
cp: overwrite `/home/kitten/.ssh/known_hosts'? y
[root@wps85 .ssh]# ls -la
total 44
drwx------  2 kitten kitten 4096 Mar 10 10:18 .
drwxr-xr-x 57 kitten kitten 4096 Aug  2 12:38 ..
-rw-------  1 kitten kitten 1743 Jan  5  2016 cheeyung
-rw-r--r--  1 kitten kitten  400 Jan  5  2016 cheeyung.pub
-rw-------  1 kitten kitten 1766 Aug  2 14:33 id_rsa
-rw-r--r--  1 kitten kitten  406 Aug  2 14:33 id_rsa.pub
-rw-r--r--  1 kitten kitten  840 Aug  2 14:33 known_hosts
-rw-------  1 kitten kitten 1675 Dec 30  2015 kwangchin
-rw-r--r--  1 kitten kitten  400 Dec 30  2015 kwangchin.pub
-rw-------  1 kitten kitten 1671 Nov 17  2015 ta_gerrit_id_rsa
-rw-r--r--  1 kitten kitten  400 Nov 17  2015 ta_gerrit_id_rsa.pub
[root@wps85 .ssh]# chmod 644 id_rsa
[root@wps85 .ssh]# ls -la
total 44
drwx------  2 kitten kitten 4096 Mar 10 10:18 .
drwxr-xr-x 57 kitten kitten 4096 Aug  2 12:38 ..
-rw-------  1 kitten kitten 1743 Jan  5  2016 cheeyung
-rw-r--r--  1 kitten kitten  400 Jan  5  2016 cheeyung.pub
-rw-r--r--  1 kitten kitten 1766 Aug  2 14:33 id_rsa
-rw-r--r--  1 kitten kitten  406 Aug  2 14:33 id_rsa.pub
-rw-r--r--  1 kitten kitten  840 Aug  2 14:33 known_hosts
-rw-------  1 kitten kitten 1675 Dec 30  2015 kwangchin
-rw-r--r--  1 kitten kitten  400 Dec 30  2015 kwangchin.pub
-rw-------  1 kitten kitten 1671 Nov 17  2015 ta_gerrit_id_rsa
-rw-r--r--  1 kitten kitten  400 Nov 17  2015 ta_gerrit_id_rsa.pub