add and remove pip install/uninstall from requirements.txt automatically

.bashrc

# add pip install/uninstall to requirements.txt automatically
pipr() {
 if [ "$1" == "install" ]; then
    pip $1 $2
    pip freeze | grep -i $2 >> requirements.txt
    echo ok, added $2 as:
    tail -n1 requirements.txt
 fi
 if [ "$1" == "uninstall" ]; then
    echo y | pip $1 $2 >> .pipremoved
    grep -i "successfully uninstalled" .pipremoved | grep -o -i $2 >> requirements.removed
    cp requirements.txt requirements.bak
    tail -n1 requirements.removed | xargs -I{}  grep -v {} requirements.bak > requirements.txt
    echo ok, removed:
    tail -n1 requirements.removed
    rm .pipremoved >/dev/nul
 fi
}

usage:

# install some-package
$ pipr install some-package
$ cat requirements.txt
...
some-package==1.0.0

# remove some-package
$ pipr uninstall somepackage
$ cat requirements.txt
...

so you don't have to manually manage requirements.txt. You could use pip freeze > requirements.txt but this generates a lot of clutter: pip freeze does not take into account dependencies, and so once you install more than a couple of packages, your requirements.txt becomes cluttered. pipr only adds what you actually installed.