How to know which shell I am using in Linux

echo $0
  • ($0) Expands to the name of the shell or shell script

How to know my default shell in Linux

echo $SHELL

For example:

[j@localhost ~]$ echo $SHELL   #Default shell is bash
/bin/bash
[j@localhost ~]$ echo $0       #Current shell is also bash
bash
[j@localhost ~]$ ksh           #switch to ksh
$ echo $SHELL                  #Default shell is still bash
/bin/bash
$ echo $0                      #Current shell becomes ksh now
ksh