Pack is a simple version of the traditional Unix ar tool. It implements only the operations needed by Go.
go tool pack op file.a [name...]
Pack applies the operation to the archive, using the names as arguments to the operation.
The operation op is given by one of these letters:
c append files (from the file system) to a new archive p print files from the archive r append files (from the file system) to the archive t list files from the archive x extract files from the archive
For the p, t, and x commands, listing no names on the command line causes the operation to apply to all files in the archive.
In contrast to Unix ar, the r operation always appends to the archive, even if a file with the given name already exists in the archive. In this way pack's r operation is more like Unix ar's rq operation.
Adding the letter v to an operation, as in pv or rv, enables verbose operation: For the c and r commands, names are printed as files are added. For the p command, each file is prefixed by the name on a line by itself. For the t command, the listing includes additional file metadata. For the x command, names are printed as files are extracted.