ar \- archive (library) file format
is used to combine several files into
Archives are used mainly as libraries to be searched
has a magic number at the start,
followed by the constituent files, each preceded by a file header.
The magic number and header layout as described in the
.ta \w'#define 'u +\w'ARMAG 'u
The name is a null-terminated string; the date is in the
the user ID and group ID are numbers; the mode is a bit pattern
the size is counted in bytes.
Each file begins on a word boundary;
a null byte is inserted between files if necessary.
Nevertheless the size given reflects the
actual size of the file exclusive of padding.
Notice there is no provision for empty areas in an archive
Coding user and group IDs as characters is a botch.