hg update is a command in Mercurial (Hg) that allows users to update their working directory to a specific changeset, typically a revision or a branch head. Here’s a detailed explanation of hg update:
- Overview: In a Mercurial repository, the working directory represents the state of files at a particular point in the repository’s history. The hg update command enables users to transition their working directory to a different state, as specified by a changeset identifier.
- Command Usage: To use hg update, users provide a changeset identifier as an argument to the command. This identifier can be a revision number, a branch name, a tag, or any other valid changeset reference. When executed, hg update adjusts the working directory to match the state of the specified changeset.
- Working Directory Changes: When hg update is invoked, Mercurial updates the working directory to reflect the files and directory structure associated with the specified changeset. If there are local modifications in the working directory that conflict with the changeset being updated to, Mercurial may prompt the user to resolve conflicts before proceeding.
- Branch Switching: One common use case for hg update is switching between branches in a repository. By specifying the name of a different branch, users can transition their working directory to the state corresponding to the latest changeset on that branch.
- Documentation Reference: The Mercurial documentation provides comprehensive information about hg update, including detailed explanations of its usage, options, and behavior. Users can refer to this documentation for guidance on effectively utilizing hg update in their version control workflows.
“hg update” Command Examples
1. Update to the tip of the current branch:
# hg update
2. Update to the specified revision:
# hg update --rev [revision]
3. Update and discard uncommitted changes:
# hg update --clean
4. Update to the last commit matching a specified date:
# hg update --date [dd-mm-yyyy]
Summary
In summary, hg update is a versatile command in Mercurial that facilitates the transition of the working directory to different states within the repository’s history. Whether switching branches, revisiting past revisions, or synchronizing with remote changes, hg update empowers users to manage their working directory effectively.