When I ssh into a ubuntu machine, what kind of shell am I using

All we need is an easy explanation of the problem, so here it is.

I keep reading about interactive, non-interactive, login, and non-login shells.

(This is in the context of which of the .bash* files is read).

I don’t understand what each type of shell is, so let’s start with the basics.

If I ssh from my mac to my ubuntu machine, what type of shell is getting fired up?

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

If you SSH into your Ubuntu box, you’re getting an interactive login shell. Here’s the difference:

  • Interactive vs. non-interactive: Any shell where you can type at a prompt is interactive. In fact, many scripts test for the variable $PS1 which holds the prompt string to find out whether they’re interactive. If a shell is executing a shell script, it’s non-interactive.

    So, if you do ssh yourbox.example.com, you’ll get an interactive shell, asuming default settings, while if you do ssh yourbox.example.com mighty_shellscript.sh, you’ll end up with a non-interactive shell and your SSH session will terminate when the script terminates.

  • Login vs. non-login: When you log in from the console or remotely (such as SSH), or when you pass the -l option to bash, you get a login shell. Otherwise–such as when you open up a terminal window–you get a non-login shell.

    To test whether a shell is a login shell, check whether its command name is -bash instead of bash:

    ps -ef | grep [b]ash
    

Method 2

You get an interactive login shell. But don’t take it for granted, check it yourself.

This tells you that you have a login shell (from man bash):

# shopt | grep login
login_shell     on

This tells you that you have an interactive shell, look for the i (from man bash):

# echo $-
himBH

The interactive login shell you get has read /etc/profile and than one of ~/.bash_profile, ~/.bash_login and ~/.profile, as explained in man bash:

When bash is invoked as an interactive login shell, or as a
non-interactive shell with the –login option, it first reads and
executes commands from the file
/etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that
order, and reads and executes com‐
mands from the first one that exists and is readable.
The –noprofile option may be used when the shell is started to inhibit this behavior.

Method 3

The ssh(1) man page says,

If command is specified, it is executed on the remote host instead of a login shell.

and

When the user’s identity has been accepted by the server, the server either executes the given command, or logs into the machine and gives the user a normal shell on the remote machine.

Those suggest to me that the shell you’re getting is a login shell.

Method 4

Try this command.

[[email protected] ~]$ echo $SHELL
/bin/bash

you are getting this output because your shell type is stored in this variable SHELL.

To know your environment variable type this command

[[email protected] ~]$ env
.
.
.
HOSTNAME=localhost.localdomain
SHELL=/bin/bash
HISTSIZE=1000
USER=max
.
.
.

while typing echo $SHELL it will print the value whatever stored here

This value gets updated for every bootup

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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