gustaebel / cdenv

Manage different bash environments for different directories

cdenv

Manage different bash environments for different directories.

About

cdenv is similar to such tools as autoenv, direnv, smartcd, and funky. It tries to find the right balance between being very powerful while being still easy to use, and follows the Principle of Least Surprise.

How it works

cdenv will be triggered before each prompt and check for the existence of a shell script called .cdenv.sh in the current working directory. If there is one, cdenv makes a snapshot of the current environment, sources the .cdenv.sh script and makes another snapshot. cdenv then compares the two snapshots of the environment and creates a file in ~/.cache/cdenv which can later be used to undo the changes when you leave the directory.

As you would expect, changes to the environment stack on top of each other the deeper you go in the directory tree. Besides adding new shell definitions, existing definitions may be removed or overwritten by .cdenv.sh files further down the tree. All changes applied by .cdenv.sh files are automatically undone when you leave their respective directory, there is no need to write separate code that does that.

If you cd deep into a directory structure, cdenv will check if there are .cdenv.sh files between the old and the new current working directory that have not yet been sourced. Every .cdenv.sh file is loaded by changing into that respective directory, sourcing the script file and changing back to the original directory.

A .cdenv.sh file is a plain shell script, that is only sourced once when you enter the directory it is in. All the definitions of environment variables, functions, aliases and the rest of the code it contains are executed in the exact order and manner you would expect. There is no need to modify your code to work with cdenv.

All changes that are made to the environment are specific to current shell process, e.g. it is possible to define a certain function only if certain conditions are met. Only the things that were changed are being restored to their old values, when you leave the directory.

cdenv installs itself by appending to bash's PROMPT_COMMAND array variable.

Features

• Keeps track of all environment changes and undoes them selectively when you leave the directory later.
• Supports adding, removing and modifying:
  • Environment variables
  • Shell functions
  • Aliases
  • Shell options
• Supports oneshot shell code that is executed once when the directory is entered.
• Uses plain shell code, no imposed quirky constraints.
• Support for bash >= 4.0 only.

Commands

• help

  Show a helpful message about cdenv.

• reload

  Unload and reload the complete cdenv environment and all .cdenv.sh in the current directory hierarchy.

• edit

  Load the .cdenv.sh from the current working directory in the $EDITOR for editing and reload it after that. If -b/--base is given, the .cdenv.sh from the nearest base is opened. If a <name> is given, open the script file where this name has most recently been defined.

Settings

Some of cdenv's settings can be customized with a file called ~/.cdenvrc.sh.

• CDENV_VERBOSE={0|1|2}

  Produce verbose output useful for debugging, default is 0.

• CDENV_GLOBAL={0|1}

  If set to 1, the changes in ~/.cdenv.sh apply globally, regardless of whether the current working directory is located inside the home directory, default is 1.

• CDENV_AUTORELOAD={0|1}

  If set to 1, shell scripts from CDENV_PATH and .cdenv.sh files are automatically reloaded if they are changed, loaded if they are added and unloaded if they are removed. If set to 0, you have to use cdenv edit or cdenv reload if you want changes to your shell scripts appear in your current shell environment. The default is 0.

• CDENV_FILE

  Use a script filename different from the default .cdenv.sh to prevent accidentally executing other people's shell code from a tar file or source repo.

• CDENV_PATH

  A colon-separated list of directories (similar to PATH) with shell scripts to load on startup. The files must end with .sh and are loaded in alphabetical order.

• CDENV_COLOR={0|1} If set to 1, use colored output for error messages and debug messages (if CDENV_VERBOSE > 0), default is 1.

Installation from the shar archive

Prerequisites

• curl / wget

Installation

Installation for the current user:

mkdir ~/.cdenv
cd ~/.cdenv
curl -sL https://github.com/gustaebel/cdenv/releases/latest/download/cdenv.shar | bash
source cdenv.sh install

To update this installation:

bash ~/.cdenv/cdenv.sh update

Installation from git

Prerequisites

• bash >= 4.0
• coreutils
• make
• rust

Installation

Installation for the current user:

git clone https://github.com/gustaebel/cdenv.git ~/.cdenv
cd .cdenv
make
source cdenv.sh install

To update this installation:

git pull
make
cdenv reload