* matches a sequence of 0 or more characters
? matches exactly 1 character
\nnn matches the character having octal code nnn
The last three fields are clearly the modification date and time of the file, and its name. The case of the filename is respected; thus files which come from MS-DOS PKZIP are always capitalized. If the file was zipped with a stored directory name, that is also displayed as part of the filename.
The second and third fields indicate that the file was zipped under Unix with version 1.5 of Zip (a beta version). Since it comes from Unix, the file permissions at the beginning of the line are printed in Unix format. The uncompressed file-size (2802 in this example) is the fourth field.
The fifth field consists of two characters, either of which may take on several values. The first character may be either `t' or `b', indicating that Zip believes the file to be text or binary, respectively; but if the file is encrypted, ZipInfo notes this fact by capitalizing the character (`T' or `B'). The second character may also take on four values, depending on whether there is an extended local header and/or an ``extra field'' associated with the file (explained in PKWare's APPNOTE.TXT). If neither exists, the character will be a hyphen (`-'); if there is an extended local header but no extra field, `l'; if the reverse, `x'; and if both exist, `X'. Thus the file in this example is (apparently) a text file, is not encrypted, and has neither an extra field nor an extended local header associated with it. The example below, on the other hand, is an encrypted binary file with an extra field:
Extra fields are used by PKWare for authenticity verification(?) and possibly other purposes, and by Info-ZIP's Zip 1.6 and later to store OS/2, Macintosh and VMS file attributes. This example presumably falls into the latter class, then. Note that the file attributes are listed in VMS format. Other possibilities for the host operating system include OS/2 with High Performance File System (HPFS), DOS or OS/2 with File Allocation Table (FAT) file system, and Macintosh, denoted as follows:
File attributes in the first two cases are indicated in a DOS-like format, where the file may or may not have its archive bit set; may be hidden or not; may be read-write or read-only; and may be a system file or not. If the attributes are too long, the version number of the encoding software is omitted. (The information is still available in the verbose listing, however.) Interpretation of Macintosh file attributes needs some work yet.
Finally, the sixth field indicates the compression method and possible sub-method used. There are six methods known at present: storing (no compression), reducing, shrinking, imploding, tokenizing, and deflating. In addition, there are four levels of reducing (1 through 4); four types of imploding (4K or 8K sliding dictionary, and 2 or 3 Shannon-Fano trees); and three levels of deflating (fast, normal, maximum compression). ZipInfo represents these methods and their sub-methods as follows: ``stor''; ``re:1,'' ``re:2,'' etc.; ``shrk''; ``i4:2,'' ``i8:3,'' etc.; ``tokn''; and ``defF,'' ``defN,'' and ``defX.''
The medium and long listings are almost identical to the short format except that they add information on the file's compression. The medium format indicates the file's compression factor as a percentage:
In this example, the file has been compressed by more than a factor of five; the compressed data are only 19% of the original size. The long format gives the compressed file's size in bytes, instead:
In addition to individual file information, a default zipfile listing also includes header and trailer lines:
The header line gives the name of the archive, its total size, and the total number of files; the trailer gives the number of files listed, their total uncompressed size, and their total compressed size (not including any of Zip's internal overhead). If, however, one or more filespecs are provided, the header and trailer lines are not listed. This behavior is also similar to that of Unix's ``ls -l''; it may be overridden by specifying the -h and -t options explicitly. In such a case the listing format must also be specified explicitly, since -h or -t (or both) in the absence of other options implies that ONLY the header or trailer line (or both) is listed. See the EXAMPLES section below for a semi-intelligible translation of this nonsense.
The verbose listing is self-explanatory. It also lists file comments and the zipfile comment, if any, and the number of bytes of OS/2 extended attributes stored. Note that the latter number will in general NOT match the number given by OS/2's ``dir'' command; OS/2 always reports the number of bytes required in 16-bit format, whereas ZipInfo always reports the 32-bit storage.
The default listing format, as noted above, corresponds roughly to the "zipinfo -hst" command (except when individual zipfile members are specified). A user who prefers the long-listing format (-l) can make use of the ZIPINFO environment variable to change this default:
If, in addition, the user dislikes the trailer line, ZipInfo's concept of ``negative options'' may be used to override the default inclusion of the line. This is accomplished by preceding the undesired option with one or more minuses: e.g., ``-l-t'' or ``--tl'', in this example. The first hyphen is the regular switch character, but the one before the `t' is a minus sign. The dual use of hyphens may seem a little awkward, but it's reasonably intuitive nonetheless: simply ignore the first hyphen and go from there. It is also consistent with the behavior of the Unix command nice(1).
To produce a basic, long-format listing (not verbose), including header and totals lines, use -l:
To list the complete contents of the archive without header and totals lines, either negate the -h and -t options or else specify the contents explicitly:
(where the backslash is required only if the shell would otherwise expand the `*' wildcard, as in Unix when globbing is turned on--double quotes around the asterisk would have worked as well). To turn off the totals line by default, use the environment variable (C shell is assumed here):
To get the full, short-format listing of the first example again, given that the environment variable is set as in the previous example, it is necessary to specify the -s option explicitly, since the -t option by itself implies that ONLY the footer line is to be printed:
The -s option, like -m and -l, includes headers and footers by default, unless otherwise specified. Since the environment variable specified no footers and that has a higher precedence than the default behavior of -s, an explicit -t option was necessary to produce the full listing. Nothing was indicated about the header, however, so the -s option was sufficient. Note that both the -h and -t options, when used by themselves or with each other, override any default listing of member files; only the header and/or footer are printed. This behavior will be more useful when ZipInfo accepts wildcards for the zipfile name; one may then summarize the contents of all zipfiles with a single command.
To list information on a single file within the archive, in medium format, specify the filename explicitly:
The specification of any member file, as in this example, will override the default header and totals lines; only the single line of information about the requested file will be printed. This is intuitively what one would expect when requesting information about a single file. For multiple files, it is often useful to know the total compressed and uncompressed size; in such cases -t may be specified explicitly:
Finally, to get maximal information about the ZIP archive, use the verbose option. It is usually wise to pipe the output into a filter such as more(1):