Shell often exits after sourcing .bashrc file. Caused by infinite loop in Nvm

Question

Note

I edited the original post to get rid of red herrings and update for the newest .bashrc .

Post

I have a local Mac (using Zsh) and ssh into a EC2-based linux devbox (using Bash).

When I source ~/.bashrc on my linux computer, my shell often exits. I say "often" because it's inconsistent. I just tried running the same command twice, and the problem only appeared the second time. This problem also happens if I source inside a tmux session , so this isn't an ssh issue. When I add PS4=':${BASH_SOURCE[0]##*/}:$LINENO+'; set -x PS4=':${BASH_SOURCE[0]##*/}:$LINENO+'; set -x at the top of the .bashrc file, I just see a stream of ::.bashrc:126+cdnvm /home/jalvarado messages. Based on this output, I think the last successfully-executed command is alias cd='cdnvm' .

::.bashrc:124+'[' -s /home/jalvarado/.nvm/bash_completion ']'
::.bashrc:124+. /home/jalvarado/.nvm/bash_completion
:::bash_completion:5+command -v nvm
:::bash_completion:86+[[ -n '' ]]
:::bash_completion:96+complete -o default -F __nvm nvm
::.bashrc:167+alias cd=cdnvm
::.bashrc:168+cdnvm /home/jalvarado
::.bashrc:126+cdnvm /home/jalvarado
::.bashrc:126+cdnvm /home/jalvarado
::.bashrc:126+cdnvm /home/jalvarado
::.bashrc:126+cdnvm /home/jalvarado
...
::.bashrc:126+cdnvm /home/jalvarado
::.bashrc:126+cdnvm /home/jalvarado
::.bashrc:126+cdnvm /home/jalvarado
::.bashrc:126+cdnvm /home/jalvarado
Connection to devrestricted-jalvarado.ec2.pin220.com closed.

Despite this, I have no problem starting a new shell. When I ssh into my devbox or start a new tmux session, I don't see any output. In fact, I no longer see "hello" as part of my echo "hello" command in the.bashrc, which I was using to debug earlier until the echo mysteriously disappeared.

I'm at a loss for how to investigate this. Does anyone have suggestions?

Here are the full contents of my .bashrc file. Almost all of it was programmatically generated (not by me). The only lines I manually added are the pyenv lines at the bottom and the debugging line at the very top.

# For debugging
PS4=':${BASH_SOURCE[0]##*/}:$LINENO+'; set -x

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
    # We have color support; assume it's compliant with Ecma-48
    # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
    # a case would tend to support setf rather than setaf.)
    color_prompt=yes
    else
    color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# colored GCC warnings and errors
#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion
cdnvm() {
  cd "$@";
  nvm_path=$(nvm_find_up .nvmrc | tr -d '\n')

  # If there are no .nvmrc file, use the default nvm version
  if [[ ! $nvm_path = *[^[:space:]]* ]]; then

    declare default_version;
    default_version=$(nvm version default);

    # If there is no default version, set it to `node`
    # This will use the latest version on your machine
    if [[ $default_version == "N/A" ]]; then
      nvm alias default node;
      default_version=$(nvm version default);
    fi

    # If the current version is not the default version, set it to use the default version
    if [[ $(nvm current) != "$default_version" ]]; then
      nvm use default;
    fi

    elif [[ -s $nvm_path/.nvmrc && -r $nvm_path/.nvmrc ]]; then
    declare nvm_version
    nvm_version=$(<"$nvm_path"/.nvmrc)

    declare locally_resolved_nvm_version
    # `nvm ls` will check all locally-available versions
    # If there are multiple matching versions, take the latest one
    # Remove the `->` and `*` characters and spaces
    # `locally_resolved_nvm_version` will be `N/A` if no local versions are found
    locally_resolved_nvm_version=$(nvm ls --no-colors "$nvm_version" | tail -1 | tr -d '\->*' | tr -d '[:space:]')

    # If it is not already installed, install it
    # `nvm install` will implicitly use the newly-installed version
    if [[ "$locally_resolved_nvm_version" == "N/A" ]]; then
      nvm install "$nvm_version";
    elif [[ $(nvm current) != "$locally_resolved_nvm_version" ]]; then
      nvm use "$nvm_version";
    fi
  fi
}
alias cd='cdnvm'
cd $PWD

export PYENV_ROOT="$HOME/.pyenv"
command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init -)"

echo "hello"

Answer 1

The problem shown by the xtrace log is the cd inside cdnvm just calling cdnvm again because of the alias cd=cdnvm .

To fix it, change:

cdnvm() {
  cd "$@"

to

cdnvm() {
  builtin cd "$@";

...forcing the original/built-in copy of cd to be used, bypassing the alias.

Answer 2

It turns out that my linux machine had outdated nvm code. There was an infinite loop issue that NVM fixed last year. I'd recommend taking the most up-to-date version of the code they have.

Their solution was similar to @Charles's: use command cd instead of just cd , which they aliased, creating an infinite loop.