Git Update Ref Command

git-update-ref(1) ================= NAME ---- git-update-ref - Update the object name stored in a ref safely SYNOPSIS -------- [synopsis] git update-ref [-m <reason>] [--no-deref] -d <ref> [<old-oid>] git update-ref [-m <reason>] [--no-deref] [--create-reflog] <ref> <new-oid> [<old-oid>] git update-ref [-m <reason>] [--no-deref] --stdin [-z] [--batch-updates] DESCRIPTION ----------- Given two arguments, stores the <new-oid> in the <ref>, possibly dereferencing the symbolic refs. E.g. `git update-ref HEAD <new-oid>` updates the current branch head to the new object. Given three arguments, stores the <new-oid> in the <ref>, possibly dereferencing the symbolic refs, after verifying that the current value of the <ref> matches <old-oid>. E.g. `git update-ref refs/heads/master <new-oid> <old-oid>` updates the master branch head to <new-oid> only if its current value is <old-oid>. You can specify 40 "0" or an empty string as <old-oid> to make sure that the ref you are creating does not exist. The final arguments are object names; this command without any options does not support updating a symbolic ref to point to another ref (see linkgit:git-symbolic-ref[1]). But `git update-ref --stdin` does have the `symref-*` commands so that regular refs and symbolic refs can be committed in the same transaction. If --no-deref is given, <ref> itself is overwritten, rather than the result of following the symbolic pointers. With `-d`, it deletes the named <ref> after verifying that it still contains <old-oid>. With `--stdin`, update-ref reads instructions from standard input and performs all modifications together. Specify commands of the form: update SP <ref> SP <new-oid> [SP <old-oid>] LF create SP <ref> SP <new-oid> LF delete SP <ref> [SP <old-oid>] LF verify SP <ref> [SP <old-oid>] LF symref-update SP <ref> SP <new-target> [SP (ref SP <old-target> | oid SP <old-oid>)] LF symref-create SP <ref> SP <new-target> LF symref-delete SP <ref> [SP <old-target>] LF symref-verify SP <ref> [SP <old-target>] LF option SP <opt> LF start LF prepare LF commit LF abort LF With `--create-reflog`, update-ref will create a reflog for each ref even if one would not ordinarily be created. With `--batch-updates`, update-ref executes the updates in a batch but allows individual updates to fail due to invalid or incorrect user input, applying only the successful updates. However, system-related errors—such as I/O failures or memory issues—will result in a full failure of all batched updates. Any failed updates will be reported in the following format: rejected SP (<old-oid> | <old-target>) SP (<new-oid> | <new-target>) SP <rejection-reason> LF Quote fields containing whitespace as if they were strings in C source code; i.e., surrounded by double-quotes and with backslash escapes. Use 40 "0" characters or the empty string to specify a zero value. To specify a missing value, omit the value and its preceding SP entirely. Alternatively, use `-z` to specify in NUL-terminated format, without quoting: update SP <ref> NUL <new-oid> NUL [<old-oid>] NUL create SP <ref> NUL <new-oid> NUL delete SP <ref> NUL [<old-oid>] NUL verify SP <ref> NUL [<old-oid>] NUL symref-update SP <ref> NUL <new-target> [NUL (ref NUL <old-target> | oid NUL <old-oid>)] NUL symref-create SP <ref> NUL <new-target> NUL symref-delete SP <ref> [NUL <old-target>] NUL symref-verify SP <ref> [NUL <old-target>] NUL option SP <opt> NUL start NUL prepare NUL commit NUL abort NUL In this format, use 40 "0" to specify a zero value, and use the empty string to specify a missing value. In either format, values can be specified in any form that Git recognizes as an object name. Commands in any other format or a repeated <ref> produce an error. Command meanings are: update::

The git update-ref command is used to update the object name stored in a ref safely, allowing for the creation, deletion, and modification of references in a Git repository. It provides various options to handle different scenarios, including updating a ref to point to a new object, deleting a ref, and creating a reflog. The command also supports batch updates and can read instructions from standard input, making it a versatile tool for managing references in a Git repository.