Helpful git aliases

git-aliases.sh

#!/usr/bin/env bash
# bash: `bash ./alias.sh` (requires sudo in macOS)
# zsh: `zsh ./alias.sh`

main() {
  local -ra aliases=(
    # gitgo : Alias for git add, commit with amend, update commit date and force push
    "alias gitgo='git add . && git commit --amend --no-edit --reset-author && git push -f'"
    # gitc  : Alias for counting total characters in last commi heading
    "alias gitc='git log --pretty=format:%Creset%s --no-merges -1 | wc -c'"
    # gita  : Alias for amending to latest commit
    "alias gita='git add . && git commit --amend --no-edit --allow-empty'"
  )
  while IFS= read -r file; do
    for alias in "${aliases[@]}"; do
      set_persistent_alias "$alias" "$file"
    done
  done < <(get_alias_files)
}

set_persistent_alias() {
  local -r alias="$1"
  local -r file="$2"
  if ! create_file "$file"; then
    log_error "Failed to create the file: $file."
    return 1
  fi
  if grep -Fxq "$alias" "$file"; then
    echo "[$file] Alias already exists: $alias"
  else
    command="echo \"$alias\" >> \"$file\""
    if type "sudo" &> /dev/null; then # Git Bash on Windows does not have sudo
      command="sudo $command"
    fi
    if eval "$command"; then
      echo "[$file] Saved alias"
    else
      log_error "[$file] Failed to save alias"
    fi
  fi
  # shellcheck disable=SC1090
  source "$file"
}

get_alias_files() {
  local -a files=()
  if command_exists 'zsh'; then
    files+=("$HOME/.zshrc")
  fi
  if command_exists 'bash'; then
    if [ "$(uname -s)" == "Darwin" ]; then
      files+=("$HOME/.bash_profile")
    else # tested on Windows
      files+=("$HOME/.bashrc")
    fi
  fi
  if [ ${#files[@]} -eq 0 ]; then
    log_error 'Unkown shell'
    exit 1
  fi
  printf "%s\n" "${files[@]}"
}

create_file() {
  local file_path="$1"
  if [ -z "$file_path" ]; then
    log_error 'Missing file path.'
    return 1
  fi
  local parent_dir
  if ! parent_dir=$(dirname "$file_path"); then
    log_error "Could not determine the parent directory for the path: $file_path"
    return 1
  fi
  if [ ! -d "$parent_dir" ]; then
    echo "Creating directory: $parent_dir"
    if ! mkdir -p "$parent_dir"; then
      log_error "Failed to create the parent directory: $parent_dir"
      return 1
    fi
  fi
  if [ ! -f "$file_path" ]; then
    echo "Creating file: $file_path"
    if ! touch "$file_path"; then
      log_error "Failed to create the file: $file_path"
      return 1
    fi
  fi
}

command_exists() {
    local -r command_name="$1"
    command -v "$command_name" &> /dev/null
}

log_error() {
  local -r message="$1"
  >&2 echo "Error: $message"
}

main