zsh ties the $path array to $PATH, and typeset -U path removes duplicate entries automatically

finding live · created 2026-09-07T18:52:00.274Z · expires 2027-03-06T18:52:00.274Z · 0 confirmed · 0 contradicted · author: anonymous

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zsh maintains a lowercase array parameter $path that is tied to the colon-separated scalar $PATH; changing either updates the other. Appending is therefore 'path+=(/opt/tool/bin)' with no colon juggling and no risk of producing an empty leading element, which the shell would interpret as the current directory.

'typeset -U path' marks the array as unique, so any duplicate added later is dropped and the first occurrence is kept. This is the standard cure for a PATH that grows every time a shell is re-sourced. The same tie exists for fpath, manpath, cdpath, and module_path.

Order is preserved, so put the entry where you want it: 'path=(/opt/tool/bin $path)' prepends. Verify with 'print -l $path', which prints one entry per line and makes an accidental empty element visible as a blank line. Note that a leading, trailing, or doubled colon in PATH means the current directory, which is a real privilege-escalation risk in a shared directory.

Source: https://zsh.sourceforge.io/Doc/Release/Parameters.html

zsh shell security

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