Fixing Wrong Prompt String on a EC2 Linux Instance

One of my colleagues reported that he could not run a npm command on a EC2 instance (Amazon Linux AMI 2018.03). When I connected to the EC2 instance via SSH and found that the prompt string was using the default one which is ``\s-\v\$``. It shows the basename of the shell process with the version. The ``~/.bashrc`` file looks normal. ``~/.bashrc`` should execute ``/etc/bashrc`` where ``PROMPT_COMMAND`` will be set based on the environment variable ``TERM`` after login. ```bash # Source global definitions if [ -f /etc/bashrc ]; then . /etc/bashrc fi ``` As I am using Mac OSX Terminal, my ``TERM`` is ``xterm-256color``, which matches the first case. ``/etc/sysconfig/bash-prompt-xterm`` does not exist, hence my ``PROMPT_COMMAND`` would be ``printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"`` ```bash if [ -z "$PROMPT_COMMAND" ]; then case $TERM in xterm*) if [ -e /etc/sysconfig/bash-prompt-xterm ]; then PROMPT_COMMAND=/etc/sysconfig/bash-prompt-xterm else PROMPT_COMMAND='printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"' fi ;; screen) if [ -e /etc/sysconfig/bash-prompt-screen ]; then PROMPT_COMMAND=/etc/sysconfig/bash-prompt-screen else PROMPT_COMMAND='printf "\033]0;%s@%s:%s\033\\" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"' fi ;; *) [ -e /etc/sysconfig/bash-prompt-default ] && PROMPT_COMMAND=/etc/sysconfig/bash-prompt-default ;; esac fi ``` When an interactive shell is invoked, it executes commands from ``/etc/profile``, ``~/.bash_profile``, ``~/.bash_login``, and ``~/.profile``. The last three files does not exist. ``~/.bashrc`` is executed when the interactive shell is not a login shell. Hence, I added the following lines to ``~/.profile`` as it is executed by the command interpreter for login shell. ```bash if [ -n "$BASH_VERSION" ]; then if [ -f "$HOME/.bashrc" ]; then . "$HOME/.bashrc" fi fi ``` Restart the shell and test. It is back to normal now and $PS1 is back to ``[\u@\h \W]\$`` ``` [ec2-user@ip-xxx-xx-xx-xxx ~]$ ```