The simplest way to display file contents is using the cat line-command:
cat file.txt
The same result I get using input redirection:
cat < file.txt
Then, what is the difference between them?
I was working through a tutorial and saw use of both cat myfile.txt and cat < myfile.txt. Is there a difference between these two sequences of commands? It seems both print the contents of a file to the shell.
@kauray Generally, as the admin of the system, you would know what ports you run various services on. If that's not something that you keep track of, then starting any service on those ports would fail if the ports were not available.
This means that you could probably follow the instructions and start Nginx on port 8080 etc. and see if that worked or not. If it doesn't, check the logs and it may tell you that the port is already in use.
netstat -lnp will list the pid and process name next to each listening port. This will work under Linux, but not all others (like AIX.) Add -t if you want TCP only.
# netstat -lntp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address St...
:52675677 ssh-keyscan is a utility for gathering the public SSH host keys of a
number of hosts. It was designed to aid in building and verifying
ssh_known_hosts files, the format of which is documented in sshd(8).
ssh-keyscan provides a minimal interface suitable for use by shell and
perl scripts.
It adds the host key for github.com to your known_hosts file.
That way, the first time you connect to the host, you will not be asked whether the host key is correct or not.
To access a private GitHub repository, you (your github account) must be registered as a collaborator on the project. This is nothing that you can do yourself, but an existing admin for that project can add you to it. In your own github account, I believe you should add your SSH public key, and then use a git:// URL to check out the private repo once you have been added to the project.
This has nothing to do with the ssh-keyscan command.
jenkins@479a1bec5451:~/.ssh$ ls
id_rsa id_rsa.pub
jenkins@479a1bec5451:~/.ssh$ git clone github.com/shamhub/todobackend.git
Cloning into 'todobackend'...
Username for 'https://github.com':
$ git clone git@github.com:shamhub/todobackend.git
Cloning into 'todobackend'...
The authenticity of host 'github.com (140.82.114.4)' can't be established.
RSA key fingerprint is SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8.
Are you sure you want to continue connecting (yes/no)?
Hmmm... The public host key of github.com is now in your known_hosts file. Every time you connect to github.com using SSH, that key will be verified. You will be notified if there is a difference.
It is not symmetric in the sense that Github could connect to you (they can't, because they don't have your private key).
They can't authenticate as you anywhere because they don't have your private key. This means it's not symmetric.
Key-based encryption/authentication is not symmetric.
For repositories on GitHub, try:
git clone ssh://git@github.com/<user>/<repository name>.git
For setting up git to clone via ssh see:
Generating SSH Keys and add your generated key in Account Settings -> SSH Keys
Cloning with SSH
In this answer... it recommends to use another syntax git clone ssh://git@github.com/shamhub/todobackend.git
@overexchange I can imagine that it is the name of the user on the remote system that manages the Git service. A service account on github.com. It is likely responsible for making sure that you are properly authenticated to the repository in the later part of the address.
Or, it's just a string that github.com uses to identify git command requests (as opposed to, for example, one of their employees wanting to log in over SSH).
@Biswapriyo the former; see the kernel itself for details. The latter is the x86-64 calling convention for non-syscalls (function calls inside programs).
I was working through a tutorial and saw use of both cat myfile.txt and cat < myfile.txt. Is there a difference between these two sequences of commands? It seems both print the contents of a file to the shell.
netstat -lnp will list the pid and process name next to each listening port. This will work under Linux, but not all others (like AIX.) Add -t if you want TCP only.
# netstat -lntp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address St...
For repositories on GitHub, try:
git clone ssh://git@github.com/<user>/<repository name>.git
For setting up git to clone via ssh see:
Generating SSH Keys and add your generated key in Account Settings -> SSH Keys
Cloning with SSH
