git-update-ref(1) ================= NAME ---- git-update-ref - update the object name stored in a ref safely SYNOPSIS -------- `git-update-ref` [] DESCRIPTION ----------- Given two arguments, stores the in the , possibly dereferencing the symbolic refs. E.g. `git-update-ref HEAD ` updates the current branch head to the new object. Given three arguments, stores the in the , possibly dereferencing the symbolic refs, after verifying that the current value of the matches . E.g. `git-update-ref refs/heads/master ` updates the master branch head to only if its current value is . It also allows a "ref" file to be a symbolic pointer to another ref file by starting with the four-byte header sequence of "ref:". More importantly, it allows the update of a ref file to follow these symbolic pointers, whether they are symlinks or these "regular file symbolic refs". It follows *real* symlinks only if they start with "refs/": otherwise it will just try to read them and update them as a regular file (i.e. it will allow the filesystem to follow them, but will overwrite such a symlink to somewhere else with a regular filename). In general, using git-update-ref HEAD "$head" should be a _lot_ safer than doing echo "$head" > "$GIT_DIR/HEAD" both from a symlink following standpoint *and* an error checking standpoint. The "refs/" rule for symlinks means that symlinks that point to "outside" the tree are safe: they'll be followed for reading but not for writing (so we'll never write through a ref symlink to some other tree, if you have copied a whole archive by creating a symlink tree). Author ------ Written by Linus Torvalds . GIT --- Part of the gitlink:git[7] suite