Automatically add new folders to your path without needed to manually edit a script

addtopath

#!/usr/bin/env bash

# Copyright (c) 2022 Daniel Garcia-Briseno
# Written: 2022-04-06
# Updated: 2022-04-07 - added customization with the environment variable
#                       ADDTOPATH_TARGET
#                     - Added ability to request sudo permission
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.  
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.

# By default this script will modify /etc/profile with the paths you
# provide. You can change this behaviour by specifying the target
# script to update in the environment variable ADDTOPATH_TARGET

set -e

# Alias inputs
target_folder=$1
description=$2
needs_privileges=0
file_to_update=/etc/profile

# Check if the user has set the ADDTOPATH_TARGET environment
# variable and it is a valid file. If not, then default to
# /etc/profile 
update_file_to_update() {
    # If $ADDTOPATH_TARGET is set and the target file exists
    if [ ! -z $ADDTOPATH_TARGET ]
    then
	if [ -f $ADDTOPATH_TARGET ]
        then
	    file_to_update=$ADDTOPATH_TARGET
	fi
    fi
}

request_permission_if_needed() {
    if [ ! -w $file_to_update ]
    then
	echo "Elevated privileges required to write to $file_to_update"
	elevate_privileges
	needs_privileges=1
    fi
}

# Relies on the assumption that after running a sudo command once,
# then sudo is allowed without a password
elevate_privileges() {
    sudo echo "" > /dev/null
}

# Function for usage text
print_usage() {
    echo "Usage:"
    echo "    " $0 "target_folder" "description"
}

update_path() {
    # Create a new line in the user's bashrc
    # Add the description as a comment
    # Then update the path
    echo "" >> $file_to_update
    echo "#" $description >> $file_to_update
    echo export PATH=$full_path_to_folder:\$PATH >> $file_to_update
}

sudo_update_path() {
    # Is there a way to wrap a function with elevated privileges?
    # if we could wrap update_path with sudo, that would be ideal.
    echo "" | sudo tee -a $file_to_update > /dev/null
    echo "#" $description | sudo tee -a $file_to_update > /dev/null
    echo export PATH=$full_path_to_folder:\$PATH | sudo tee -a $file_to_update > /dev/null
}


# Confirm we have both inputs
if [ $# -ne 2 ]
then
    print_usage
    exit 1
fi

# Checks if the user has specified a different file to update through
# the environment variable ADDTOPATH_TARGET and changes file_to_update
# accordingly
update_file_to_update

# We have both inputs, proceed with adding to path
full_path_to_folder=`realpath $target_folder`    

# If file_to_update is write protected, then ask for sudo privilege
request_permission_if_needed

if [ $needs_privileges -eq 1 ]
then
    sudo_update_path
else
    update_path
fi

echo Added $full_path_to_folder to $file_to_update, source it to get your commands

That's a pretty nifty tool, but it would be better to apply your toll to /etc/profile instead of ~/.bashrc since then it would apply globaly and would work beyond different shells.

It's kind of messy now, but now it is customizable by setting an environment variable and requests sudo if elevated permissions are needed, like for /etc/profile.

That's great!