You can create a shell script to allow users to specify a custom installation directory for Git LFS and provide options for both installing and uninstalling Git LFS. Here's a sample shell script that accomplishes this [1]:

#!/bin/bash

# Function to install Git LFS in the specified directory
install_git_lfs() {
    local install_dir="$1"
    if [ -z "$install_dir" ]; then
        echo "Usage: $0 install <install_directory>"
        exit 1
    fi

    # Check if Git LFS is already installed in the specified directory
    if [ -x "$install_dir/git-lfs" ]; then
        echo "Git LFS is already installed in $install_dir."
        exit 1
    fi

    # Download and install Git LFS
    echo "Installing Git LFS in $install_dir..."
    mkdir -p "$install_dir"
    cd "$install_dir" || exit
    curl -s https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh | bash
    apt-get install git-lfs

    echo "Git LFS has been installed in $install_dir."
}

# Function to uninstall Git LFS from the specified directory
uninstall_git_lfs() {
    local install_dir="$1"
    if [ -z "$install_dir" ]; then
        echo "Usage: $0 uninstall <install_directory>"
        exit 1
    fi

    # Check if Git LFS is installed in the specified directory
    if [ -x "$install_dir/git-lfs" ]; then
        echo "Uninstalling Git LFS from $install_dir..."
        cd "$install_dir" || exit
        git lfs uninstall
        rm "$install_dir/git-lfs"

        echo "Git LFS has been uninstalled from $install_dir."
    else
        echo "Git LFS is not installed in $install_dir."
    fi
}

# Main script
if [ "$1" = "install" ]; then
    install_git_lfs "$2"
elif [ "$1" = "uninstall" ]; then
    uninstall_git_lfs "$2"
else
    echo "Usage: $0 [install|uninstall] <install_directory>"
    exit 1
fi

Save this script to a file (e.g., git-lfs-installer.sh) and make it executable with the following command:

chmod +x git-lfs-installer.sh

Usage:
To install Git LFS to a custom directory:

./git-lfs-installer.sh install /path/to/install/directory

To uninstall Git LFS from a custom directory:

./git-lfs-installer.sh uninstall /path/to/install/directory

The script uses the curl command to download and install Git LFS from the official GitHub repository. You can customize it further to suit your specific needs or adapt it for different package managers if needed.