It was my mistake that I did not track immediately the cause of the error that one day started appearing each time I'd open a new Terminal:
/usr/bin/python3: Error while finding module specification for 'virtualenvwrapper.hook_loader' (ModuleNotFoundError: No module named 'virtualenvwrapper')
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenvwrapper has been installed for
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 and that PATH is
set properly.
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenvwrapper has been installed for
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 and that PATH is
set properly.
virtualenvwrapper is, as its name says, a wrapper around virtualenv.
When a new Terminal is opened, it starts a shell which sources the first of .bash_profile, .bash_login, .profile that exists and is readable. [bash - Why must I source .bashrc every time I open terminal for aliases to work? - Ask Different]
In my case .bash_profile and .bash_login don't exist but .profile does and it sources ~/.bashrc:
$ cat ~/.profile
# ~/.profile: executed by the command interpreter for login shells.
# This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login
# exists.
# see /usr/share/doc/bash/examples/startup-files for examples.
# the files are located in the bash-doc package.
# the default umask is set in /etc/profile; for setting the umask
# for ssh logins, install and configure the libpam-umask package.
#umask 022
# if running bash
if [ -n "$BASH_VERSION" ]; then
# include .bashrc if it exists
if [ -f "$HOME/.bashrc" ]; then
. "$HOME/.bashrc"
fi
fi
# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
PATH="$HOME/bin:$PATH"
fi
# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/.local/bin" ] ; then
PATH="$HOME/.local/bin:$PATH"
fi
So I looked at ~/.bashrc and I found that some time in past I changed it to include some additional environment variables:
$ cat ~/.bashrc
...
...
# B.Komazec added:
# virtualenv and virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh
# virtualenv and virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh
...
$ cat /usr/local/bin/virtualenvwrapper.sh
...
# Run the hooks
function virtualenvwrapper_run_hook {
typeset hook_script
typeset result
hook_script="$(virtualenvwrapper_tempfile ${1}-hook)" || return 1
# Use a subshell to run the python interpreter with hook_loader so
# we can change the working directory. This avoids having the
# Python 3 interpreter decide that its "prefix" is the virtualenv
# if we happen to be inside the virtualenv when we start.
( \
virtualenvwrapper_cd "$WORKON_HOME" &&
"$VIRTUALENVWRAPPER_PYTHON" -m 'virtualenvwrapper.hook_loader' \
${HOOK_VERBOSE_OPTION:-} --script "$hook_script" "$@" \
)
result=$?
if [ $result -eq 0 ]
then
if [ ! -f "$hook_script" ]
then
echo "ERROR: virtualenvwrapper_run_hook could not find temporary file $hook_script" 1>&2
command \rm -f "$hook_script"
return 2
fi
# cat "$hook_script"
source "$hook_script"
elif [ "${1}" = "initialize" ]
then
cat - 1>&2 <<EOF
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenvwrapper has been installed for
VIRTUALENVWRAPPER_PYTHON=$VIRTUALENVWRAPPER_PYTHON and that PATH is
set properly.
EOF
fi
command \rm -f "$hook_script"
return $result
}
...
I checked which packages are installed for pip3:
$ pip3 list
...but among them were neither virtualenv nor virtualenvwrapper. So I installed them:
$ sudo pip3 install virtualenv virtualenvwrapper
Collecting virtualenv
Downloading virtualenv-20.3.1-py2.py3-none-any.whl (5.7 MB)
Collecting virtualenvwrapper
Downloading virtualenvwrapper-4.8.4.tar.gz (334 kB)
Requirement already satisfied: six<2,>=1.9.0 in /usr/lib/python3/dist-packages (from virtualenv) (1.14.0)
Requirement already satisfied: appdirs<2,>=1.4.3 in /usr/lib/python3/dist-packages (from virtualenv) (1.4.3)
Requirement already satisfied: filelock<4,>=3.0.0 in /usr/lib/python3/dist-packages (from virtualenv) (3.0.12)
Collecting distlib<1,>=0.3.1
Downloading distlib-0.3.1-py2.py3-none-any.whl (335 kB)
Collecting stevedore
Downloading stevedore-3.3.0-py3-none-any.whl (49 kB)
Collecting virtualenv-clone
Downloading virtualenv_clone-0.5.4-py2.py3-none-any.whl (6.6 kB)
Collecting pbr!=2.1.0,>=2.0.0
Using cached pbr-5.5.1-py2.py3-none-any.whl (106 kB)
Building wheels for collected packages: virtualenvwrapper
Building wheel for virtualenvwrapper (setup.py) ... done
Created wheel for virtualenvwrapper: filename=virtualenvwrapper-4.8.4-py2.py3-none-any.whl size=24833 sha256=0e77420c4c5bd24518d388768cf102170bd8b0243fd3052fdbec24b01f3bb59a
Stored in directory: /root/.cache/pip/wheels/47/15/3d/7a26eaf92e79f80a3df3ac5f8e0f0f5b7efdf24d313c594a44
Successfully built virtualenvwrapper
Installing collected packages: distlib, virtualenv, pbr, stevedore, virtualenv-clone, virtualenvwrapper
Attempting uninstall: distlib
Found existing installation: distlib 0.3.0
Not uninstalling distlib at /usr/lib/python3/dist-packages, outside environment /usr
Can't uninstall 'distlib'. No files were found to uninstall.
Successfully installed distlib-0.3.1 pbr-5.5.1 stevedore-3.3.0 virtualenv-20.3.1 virtualenv-clone-0.5.4 virtualenvwrapper-4.8.4
To verify that packages are installed indeed:
$ pip3 list
...
virtualenv 20.3.1
virtualenv-clone 0.5.4
virtualenvwrapper 4.8.4
...
I opened a new Terminal and voila - the error is gone!
For a reference, my Python paths are:
$ which python
/usr/bin/python
$ which python3
/usr/bin/python3
