Environment and PATH

PATH Order

Search Directories Left to Right

PATH is a colon-separated list of directories. Bash searches those directories from left to right when a command has no slash.

Program

Play the script to choose the first directory and build the command path Bash would find first.

path_order.sh 
#!/usr/bin/env bash

tool_dir=
PATH="$tool_dir:/usr/bin"
deploy_path="$tool_dir/deploy"
echo "$deploy_path"

#!/usr/bin/env bash

tool_dir=
PATH="$tool_dir:/usr/bin"
deploy_path="$tool_dir/deploy"
echo "$deploy_path"

#!/usr/bin/env bash

tool_dir=
PATH="$tool_dir:/usr/bin"
deploy_path="$tool_dir/deploy"
echo "$deploy_path"
PATH `PATH` tells Bash where to look for commands that are not written with a slash.
search order The leftmost directory is searched first.
command path This example models the chosen path without requiring the file to exist.