This file is part of eRCaGuy_hello_world: https://github.com/ElectricRCAircraftGuy/eRCaGuy_hello_world

See also

1. *****+ [my answer--VERY USEFUL] How do you write, import, and use libraries in Bash?

Bash libraries

These files are bash libraries which are intended to be run directly in order to run their internal unit tests, or imported (sourced) anywhere in order to use them at the command-line or in your own Bash programs!

Installation

These steps are similar to those found in ../../python/libraries/README.md.

# make a "libs_bash" dir in your home dir
mkdir -p ~/libs_bash

# symlink this entire "eRCaGuy_hello_world/bash/libraries" dir into it
cd path/to/eRCaGuy_hello_world/bash
ln -si "$(pwd)/libraries" ~/libs_bash/

# Now run this whole block at once, one time, to add this new `BASHLIBS`
# variable (which I am inventing right now) to the bottom of your ~/.bashrc
# file
# START OF BLOCK TO RUN ALL AT ONCE
cat << "EOF" >> ~/.bashrc

# Added by eRCaGuy_hello_world for importing Bash libraries: 
# https://github.com/ElectricRCAircraftGuy/eRCaGuy_hello_world
if [ -d "$HOME/libs_bash/libraries" ] ; then
    export BASHLIBS="$HOME/libs_bash/libraries"
fi
EOF
# END OF BLOCK TO RUN ALL AT ONCE

# check your new variable; you should see NO OUTPUT YET
echo "$BASHLIBS"

# re-source your terminal to receive the updates above which are now inside
# your ~/.bashrc file
. ~/.profile

# check your new variable again; you should see this as the output:
#       /home/gabriel/libs_bash/libraries
echo "$BASHLIBS"

Done!

If you take a look at the bottom of your ~/.bashrc file, you will now see this:

# Added by eRCaGuy_hello_world for importing Bash libraries: 
# https://github.com/ElectricRCAircraftGuy/eRCaGuy_hello_world
if [ -d "$HOME/libs_bash/libraries" ] ; then
    export BASHLIBS="$HOME/libs_bash/libraries"
fi

Usage

To learn what it means to source (.) or export a file or variable in Bash, see my answer here: source (.) vs export (and also some file lock [flock] stuff at the end).

You can now import (source, via the . operator) any of your Bash libraries stored inside ~/libs_bash/libraries, like this. Run this command either directly in your terminal, or inside any Bash program!

# 1. Source (import) my `floating_point_math.sh` Bash library

# Option 1: using the path manually
. ~/libs_bash/libraries/floating_point_math.sh
# or [better] (same thing)
. "$HOME/libs_bash/libraries/floating_point_math.sh"

# Option 2 [BEST]: using the `BASHLIBS` variable we just added to our
# `~/.bashrc` file
. "$BASHLIBS/floating_point_math.sh"

# 2. Now use the functions within that library
add 1.2 2.3  # result is 3.5