The PATH Variable
Understand how PATH determines which commands your shell can find and run.
When you type a command like
ls or git, how does the shell know where that program lives on your system? It doesn't search your entire hard drive — that would be painfully slow. Instead, it checks a specific list of directories, and that list is stored in the $PATH environment variable.$PATH contains a colon-separated list of directories. When you type a command, the shell walks through each directory in order, looking for an executable file with that name. The first match wins. If no directory in PATH contains the command, you get the dreaded "command not found" error.echo $PATH
# Output might look like:
# /usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbinThe
which command tells you exactly where a command lives. Running which ls shows the full path to the ls executable. This is invaluable for debugging — if a command isn't behaving as expected, which tells you which version is actually being run.which ls
# /bin/ls●
If you install a new tool and the terminal says "command not found," the fix is almost always adding the tool's directory to your PATH. Installers usually do this automatically, but knowing how PATH works helps you fix it when they don't.
In a real terminal, you can add to PATH like this:
export PATH="$PATH:/new/directory". This appends a new directory to the end of the list. Adding it to the beginning (export PATH="/new/directory:$PATH") gives it higher priority.WIN
Windows uses semicolons instead of colons to separate PATH entries (e.g., C:\Windows;C:\Program Files\Git\bin). You can edit PATH through System Properties > Environment Variables, or in PowerShell with $env:Path. In WSL, the Linux colon-separated format applies.
Try using
which to find where a command is located, and echo $PATH to see all the directories your shell searches.which echo
echo $PATHPractice