zcompdump

zcompdump is a cache file used by the Zsh shell's programmable completion system. It stores a compiled representation of the completion definitions available to the shell so that startup and subsequent completions can be performed more quickly. The file is generated and updated by the compinit function as part of Zsh's completion initialization.

Location and scope: By default it is named .zcompdump and placed in the user's home directory (that is, ~/.zcompdump). If the shell uses a nonstandard dotfile directory via the ZDOTDIR variable, the cache will be created there as $ZDOTDIR/.zcompdump. Some distributions or frameworks may use per-session or per-user caches; in practice most users interact with ~/.zcompdump.

Contents and behavior: The file contains a (typically binary) dump of the completion data used by the completion system. It is not intended to be edited by humans. Zsh reads the zcompdump on startup if present and up to date; if the file is missing or outdated, compinit rebuilds it by scanning available completion functions and commands in the fpath. This caching speeds up the initial setup and subsequent completions.

Maintenance and usage: If completions behave strangely after installing new software or making changes to completion definitions, regenerating the cache is a common remedy. This can be done by removing the existing zcompdump and reinitializing completion (often by starting a new shell or running compinit). The file is user-specific and environment-specific, and is generally safe to delete because it will be recreated automatically as needed.