See Environment Variables on Mac

A command works in one terminal but not in another, or an app cannot find a tool. The cause is usually the environment it started with.

In Terminal

printenv            # all variables
printenv PATH       # one variable
env | sort          # sorted list
echo "$PATH" | tr ':' '\n'    # PATH, one folder per line
which -a node       # every match for a command, in PATH order

The order in PATH matters: the first folder that contains the command wins.

Why apps see different values

Variables you set in ~/.zshrc exist only in shells that read that file. Apps you open from Finder, the Dock or at login do not run your shell startup files, so they usually see far fewer variables. That is why an editor launched from the Dock can miss tools your terminal finds.

Which file runs when (zsh): ~/.zshenv for every shell, ~/.zprofile for login shells, ~/.zshrc for interactive shells.

To read a variable from the login session that GUI apps inherit:

launchctl getenv NAME

A running process

For a process you own, you can see the environment it started with:

ps eww -p 12345

macOS hides this for protected system programs, and it never shows variables a process set after it started.

Careful with secrets

Environment variables often hold tokens and passwords. Do not paste printenv output into bug reports or chats.

With EnvPeek

EnvPeek shows this app’s environment and, for a PID you enter, a process’s environment, always labelled so the two are not confused. It opens PATH entry by entry and flags duplicates, missing folders and relative entries. Values that look like credentials stay hidden until you press Reveal, and nothing is logged or stored. See the EnvPeek docs.