I need to run custom binary when user logged in to system ,so that I have changed user's shell to /bin/binary to /etc/passwd but I have observed that /etc/profile file was not read when I logged in with changed user's shell So /etc/profile will be only read if user's shell is /bin/sh in /etc/passwd??
/etc/profile is not read in changed user shell
bash;shell;login
Not quite. /etc/profile will be read if the user's shell according to /etc/passwd (or LDAP, or other tool) knows how to read it and does it. If you replace /bin/sh with a binary that doesn't know how to read /etc/profile, then it won't be read.One way to fix it is obviously to fix the binary so that it knows how to handle /etc/profile.Another is to keep the user's shell set to /bin/sh, and to edit the user's $HOME/.profile to start the binary after everything else has been set up.A third way is to make the user log in using an SSH key, and edit the key so that it will start /bin/binary and disregard any other commands. You do this by editing the user's $HOME/.ssh/authorized_keys to read e.g. command=/bin/binary  ssh-dss AA.....restofkeyhere....