UNZIP Options and Modifiers (Continued)

no other options, -v lists archive files verbosely, adding to the basic -l info the compression method, compressed size, compression ratio and 32‐bit CRC. In contrast to most of the competing utilities, unzip removes the 12 addi‐ tional header bytes of encrypted entries from the compressed size numbers. Therefore, compressed size and compression ratio fig‐ ures are independent of the entry’s encryption status and show the correct compression performance. (The complete size of the encrypted compressed data stream for zipfile entries is reported by the more verbose zipinfo(1) reports, see the separate manual.) When no zipfile is specified (that is, the complete command is simply ‘‘unzip -v’’), a diagnostic screen is printed. In addi‐ tion to the normal header with release date and version, unzip lists the home Info‐ZIP ftp site and where to find a list of other ftp and non‐ftp sites; the target operating system for which it was compiled, as well as (possibly) the hardware on which it was compiled, the compiler and version used, and the compilation date; any special compilation options that might af‐ fect the program’s operation (see also DECRYPTION below); and any options stored in environment variables that might do the same (see ENVIRONMENT OPTIONS below). As a modifier it works in con‐ junction with other options (e.g., -t) to produce more verbose or debugging output; this is not yet fully implemented but will be in future releases. -z display only the archive comment. MODIFIERS -a convert text files. Ordinarily all files are extracted exactly as they are stored (as ‘‘binary’’ files). The -a option causes files identified by zip as text files (those with the ‘t’ label in zipinfo listings, rather than ‘b’) to be automatically ex‐ tracted as such, converting line endings, end‐of‐file characters and the character set itself as necessary. (For example, Unix files use line feeds (LFs) for end‐of‐line (EOL) and have no end‐ of‐file (EOF) marker; Macintoshes use carriage returns (CRs) for EOLs; and most PC operating systems use CR+LF for EOLs and con‐ trol‐Z for EOF. In addition, IBM mainframes and the Michigan Terminal System use EBCDIC rather than the more common ASCII character set, and NT supports Unicode.) Note that zip’s identi‐ fication of text files is by no means perfect; some ‘‘text’’ files may actually be binary and vice versa. unzip therefore prints ‘‘[text]’’ or ‘‘[binary]’’ as a visual check for each file it extracts when using the -a option. The -aa option forces all files to be extracted as text, regardless of the supposed file type. On VMS, see also -S. -b [general] treat all files as binary (no text conversions). This is a shortcut for ---a. -b [Tandem] force the creation files with filecode type 180 (’C’) when extracting Zip entries marked as "text". (On Tandem, -a is enabled by default, see above). -b [VMS] auto‐convert binary files (see -a above) to fixed‐length, 512‐byte record format. Doubling the option (-bb) forces all files to be extracted in this format. When extracting to standard output (-c or -p option in effect), the default conversion of text record delimiters is disabled for binary

This section continues the explanation of `unzip` options and modifiers. It describes the verbose listing of archive files with -v, including how it handles encrypted entries. It also details the archive comment display with -z. The section elaborates on modifiers like -a for text file conversion, -b for treating files as binary, and specific behaviors of -b on Tandem and VMS systems.