获取linux shell名称

Question

In my program I need to output to user which shell he is using. So in file /etc/udate-motd.d/00-header I wrote printf "$SHELL" but the problem is that even when I switching my shell to zsh, $SHELL is still equal to /bin/bash. I searched through the internet and found that I can bo it by using MyShell='ps -hp $$' , and here is again a problem. When I use it MyShell is a string with number of processes ( /etc/update-motd.d/00-header is also there) but there no word zsh .

So how can I understand which shell use the logging in person.

Answer 1

"the internet" gave you one kind of ps syntax. You've tagged this linux, so don't use BSD syntax. Try this:

ps hp $$ -o cmd

no dash

Answer 2

The users shell is determined in /etc/passwd. Why not take the information from there? You could

grep $USER /etc/passwd | cut -f7 -d:

to get the shell.