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Source: http://linux.about.com/od/commands/l/blcmdl1_gzip.htm

 

NAME

gzip, gunzip, zcat – compress or expand files

SYNOPSIS

gzip [ -acdfhlLnNrtvV19 ] [-S suffix] [ name ... ]
gunzip [ -acfhlLnNrtvV ] [-S suffix] [ name ... ]
zcat [ -fhLV ] [ name ... ]

DESCRIPTION

Gzip reduces the size of the named files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the extension .gz, while keeping the same ownership modes, access and modification times. (The default extension is -gz for VMS, z for MSDOS, OS/2 FAT, Windows NT FAT and Atari.) If no files are specified, or if a file name is "-", the standard input is compressed to the standard output. Gzip will only attempt to compress regular files. In particular, it will ignore symbolic links.

 

If the compressed file name is too long for its file system, gzip truncates it. Gzip attempts to truncate only the parts of the file name longer than 3 characters. (A part is delimited by dots.) If the name consists of small parts only, the longest parts are truncated. For example, if file names are limited to 14 characters, gzip.msdos.exe is compressed to gzi.msd.exe.gz. Names are not truncated on systems which do not have a limit on file name length.

By default, gzip keeps the original file name and timestamp in the compressed file. These are used when decompressing the file with the -N option. This is useful when the compressed file name was truncated or when the time stamp was not preserved after a file transfer.

Compressed files can be restored to their original form using gzip -d or gunzip or zcat. If the original name saved in the compressed file is not suitable for its file system, a new name is constructed from the original one to make it legal.

gunzip takes a list of files on its command line and replaces each file whose name ends with .gz, -gz, .z, -z, _z or .Z and which begins with the correct magic number with an uncompressed file without the original extension. gunzip also recognizes the special extensions .tgz and .taz as shorthands for .tar.gz and .tar.Z respectively. When compressing, gzip uses the .tgz extension if necessary instead of truncating a file with a .tar extension.

gunzip can currently decompress files created by gzip, zip, compress, compress -H or pack. The detection of the input format is automatic. When using the first two formats, gunzip checks a 32 bit CRC. For pack, gunzip checks the uncompressed length. The standard compress format was not designed to allow consistency checks. However gunzip is sometimes able to detect a bad .Z file. If you get an error when uncompressing a .Z file, do not assume that the .Z file is correct simply because the standard uncompress does not complain. This generally means that the standard uncompress does not check its input, and happily generates garbage output. The SCO compress -H format (lzh compression method) does not include a CRC but also allows some consistency checks.

Files created by zip can be uncompressed by gzip only if they have a single member compressed with the ‘deflation’ method. This feature is only intended to help conversion of tar.zip files to the tar.gz format. To extract zip files with several members, use unzip instead of gunzip.

zcat is identical to gunzip -c. (On some systems, zcat may be installed as gzcat to preserve the original link to compress.) zcat uncompresses either a list of files on the command line or its standard input and writes the uncompressed data on standard output. zcat will uncompress files that have the correct magic number whether they have a .gz suffix or not.

Gzip uses the Lempel-Ziv algorithm used in zip and PKZIP. The amount of compression obtained depends on the size of the input and the distribution of common substrings. Typically, text such as source code or English is reduced by 60-70%. Compression is generally much better than that achieved by LZW (as used in compress), Huffman coding (as used in pack), or adaptive Huffman coding (compact).

Compression is always performed, even if the compressed file is slightly larger than the original. The worst case expansion is a few bytes for the gzip file header, plus 5 bytes every 32K block, or an expansion ratio of 0.015% for large files. Note that the actual number of used disk blocks almost never increases. gzip preserves the mode, ownership and timestamps of files when compressing or decompressing.

OPTIONS

-a –ascii

Ascii text mode: convert end-of-lines using local conventions. This option is supported only on some non-Unix systems. For MSDOS, CR LF is converted to LF when compressing, and LF is converted to CR LF when decompressing.

-c –stdout –to-stdout

Write output on standard output; keep original files unchanged. If there are several input files, the output consists of a sequence of independently compressed members. To obtain better compression, concatenate all input files before compressing them.

-d –decompress –uncompress

Decompress.

-f –force

Force compression or decompression even if the file has multiple links or the corresponding file already exists, or if the compressed data is read from or written to a terminal. If the input data is not in a format recognized by gzip, and if the option –stdout is also given, copy the input data without change to the standard ouput: let zcat behave as cat. If -f is not given, and when not running in the background, gzip prompts to verify whether an existing file should be overwritten.

-h –help

Display a help screen and quit.

-l –list

For each compressed file, list the following fields:

compressed size: size of the compressed file
uncompressed size: size of the uncompressed file
ratio: compression ratio (0.0% if unknown)
uncompressed_name: name of the uncompressed file

The uncompressed size is given as -1 for files not in gzip format, such as compressed .Z files. To get the uncompressed size for such a file, you can use:

zcat file.Z | wc -c

In combination with the –verbose option, the following fields are also displayed:

method: compression method
crc: the 32-bit CRC of the uncompressed data
date & time: time stamp for the uncompressed file

The compression methods currently supported are deflate, compress, lzh (SCO compress -H) and pack. The crc is given as ffffffff for a file not in gzip format.

With –name, the uncompressed name, date and time are those stored within the compress file if present.

With –verbose, the size totals and compression ratio for all files is also displayed, unless some sizes are unknown. With –quiet, the title and totals lines are not displayed.

-L –license

Display the gzip license and quit.

-n –no-name

When compressing, do not save the original file name and time stamp by default. (The original name is always saved if the name had to be truncated.) When decompressing, do not restore the original file name if present (remove only the gzip suffix from the compressed file name) and do not restore the original time stamp if present (copy it from the compressed file). This option is the default when decompressing.

-N –name

When compressing, always save the original file name and time stamp; this is the default. When decompressing, restore the original file name and time stamp if present. This option is useful on systems which have a limit on file name length or when the time stamp has been lost after a file transfer.

-q –quiet

Suppress all warnings.

-r –recursive

Travel the directory structure recursively. If any of the file names specified on the command line are directories, gzip will descend into the directory and compress all the files it finds there (or decompress them in the case of gunzip ).

-S .suf –suffix .suf

Use suffix .suf instead of .gz. Any suffix can be given, but suffixes other than .z and .gz should be avoided to avoid confusion when files are transferred to other systems. A null suffix forces gunzip to try decompression on all given files regardless of suffix, as in:

gunzip -S "" * (*.* for MSDOS)

Previous versions of gzip used the .z suffix. This was changed to avoid a conflict with pack(1).

-t –test

Test. Check the compressed file integrity.

-v –verbose

Verbose. Display the name and percentage reduction for each file compressed or decompressed.

-V –version

Version. Display the version number and compilation options then quit.

-# –fast –best

Regulate the speed of compression using the specified digit #, where -1 or –fast indicates the fastest compression method (less compression) and -9 or –best indicates the slowest compression method (best compression). The default compression level is -6 (that is, biased towards high compression at expense of speed).

ADVANCED USAGE

Multiple compressed files can be concatenated. In this case, gunzip will extract all members at once. For example:

gzip -c file1 > foo.gz
gzip -c file2 >> foo.gz

Then

gunzip -c foo

is equivalent to

cat file1 file2

In case of damage to one member of a .gz file, other members can still be recovered (if the damaged member is removed). However, you can get better compression by compressing all members at once:

cat file1 file2 | gzip > foo.gz

compresses better than

gzip -c file1 file2 > foo.gz

If you want to recompress concatenated files to get better compression, do:

gzip -cd old.gz | gzip > new.gz

If a compressed file consists of several members, the uncompressed size and CRC reported by the –list option applies to the last member only. If you need the uncompressed size for all members, you can use:

gzip -cd file.gz | wc -c

If you wish to create a single archive file with multiple members so that members can later be extracted independently, use an archiver such as tar or zip. GNU tar supports the -z option to invoke gzip transparently. gzip is designed as a complement to tar, not as a replacement.

 

Source: http://linux.about.com/od/commands/l/blcmdl1_zip.htm

 

zip [-aABcdDeEfFghjklLmoqrRSTuvVwXyz!@$] [-b path] [-n suffixes] [-t mmddyyyy] [-tt mmddyyyy] [ zipfile [ file1 file2 ...]] [-xi list]

zipcloak [-dhL] [-b path] zipfile

zipnote [-hwL] [-b path] zipfile

zipsplit [-hiLpst] [-n size] [-b path] zipfile

DESCRIPTION

zip is a compression and file packaging utility for Unix, VMS, MSDOS, OS/2, Windows NT, Minix, Atari and Macintosh, Amiga and Acorn RISC OS.

 

It is analogous to a combination of the UNIX commands tar(1) and compress(1) and is compatible with PKZIP (Phil Katz’s ZIP for MSDOS systems).

A companion program (unzip(1L)), unpacks zip archives. The zip and unzip(1L) programs can work with archives produced by PKZIP, and PKZIP and PKUNZIP can work with archives produced by zip. zip version 2.3 is compatible with PKZIP 2.04. Note that PKUNZIP 1.10 cannot extract files produced by PKZIP 2.04 or zip 2.3. You must use PKUNZIP 2.04g or unzip 5.0p1 (or later versions) to extract them.

For a brief help on zip and unzip, run each without specifying any parameters on the command line.

The program is useful for packaging a set of files for distribution; for archiving files; and for saving disk space by temporarily compressing unused files or directories.

The zip program puts one or more compressed files into a single zip archive, along with information about the files (name, path, date, time of last modification, protection, and check information to verify file integrity). An entire directory structure can be packed into a zip archive with a single command. Compression ratios of 2:1 to 3:1 are common for text files. zip has one compression method (deflation) and can also store files without compression. zip automatically chooses the better of the two for each file to be compressed.

When given the name of an existing zip archive, zip will replace identically named entries in the zip archive or add entries for new names. For example, if foo.zip exists and contains foo/file1 and foo/file2, and the directory foo contains the files foo/file1 and foo/file3, then:

zip -r foo foo

will replace foo/file1 in foo.zip and add foo/file3 to foo.zip. After this, foo.zip contains foo/file1, foo/file2, and foo/file3, with foo/file2 unchanged from before.

If the file list is specified as -@, [Not on MacOS] zip takes the list of input files from standard input. Under UNIX, this option can be used to powerful effect in conjunction with the find(1) command. For example, to archive all the C source files in the current directory and its subdirectories:

find . -name "*.[ch]" -print | zip source -@

(note that the pattern must be quoted to keep the shell from expanding it). zip will also accept a single dash ("-") as the zip file name, in which case it will write the zip file to standard output, allowing the output to be piped to another program. For example:

zip -r – . | dd of=/dev/nrst0 obs=16k

would write the zip output directly to a tape with the specified block size for the purpose of backing up the current directory.

zip also accepts a single dash ("-") as the name of a file to be compressed, in which case it will read the file from standard input, allowing zip to take input from another program. For example:

tar cf – . | zip backup –

would compress the output of the tar command for the purpose of backing up the current directory. This generally produces better compression than the previous example using the -r option, because zip can take advantage of redundancy between files. The backup can be restored using the command

unzip -p backup | tar xf –

When no zip file name is given and stdout is not a terminal, zip acts as a filter, compressing standard input to standard output. For example,

tar cf – . | zip | dd of=/dev/nrst0 obs=16k

is equivalent to

tar cf – . | zip – - | dd of=/dev/nrst0 obs=16k

zip archives created in this manner can be extracted with the program funzip which is provided in the unzip package, or by gunzip which is provided in the gzip package. For example:

dd if=/dev/nrst0 ibs=16k | funzip | tar xvf –

When changing an existing zip archive, zip will write a temporary file with the new contents, and only replace the old one when the process of creating the new version has been completed without error.

If the name of the zip archive does not contain an extension, the extension .zip is added. If the name already contains an extension other than .zip the existing extension is kept unchanged.

OPTIONS

-a

[Systems using EBCDIC] Translate file to ASCII format.

-A

Adjust self-extracting executable archive. A self-extracting executable archive is created by prepending the SFX stub to an existing archive. The -A option tells zip to adjust the entry offsets stored in the archive to take into account this "preamble" data.

Note: self-extracting archives for the Amiga are a special case. At present, only the Amiga port of Zip is capable of adjusting or updating these without corrupting them. -J can be used to remove the SFX stub if other updates need to be made.

-B

[VM/CMS and MVS] force file to be read binary (default is text).

-Bn

[TANDEM] set Edit/Enscribe formatting options with n defined as

bit 0: Don’t add delimiter (Edit/Enscribe)

bit 1: Use LF rather than CR/LF as delimiter (Edit/Enscribe)

bit 2: Space fill record to maximum record length (Enscribe)

bit 3: Trim trailing space (Enscribe)

bit 8: Force 30K (Expand) large read for unstructured files

-b path

Use the specified path for the temporary zip archive. For example:

zip -b /tmp stuff *

will put the temporary zip archive in the directory /tmp, copying over stuff.zip to the current directory when done. This option is only useful when updating an existing archive, and the file system containing this old archive does not have enough space to hold both old and new archives at the same time.

-c

Add one-line comments for each file. File operations (adding, updating) are done first, and the user is then prompted for a one-line comment for each file. Enter the comment followed by return, or just return for no comment.

-d

Remove (delete) entries from a zip archive. For example:

zip -d foo foo/tom/junk foo/harry/\* \*.o

will remove the entry foo/tom/junk, all of the files that start with foo/harry/, and all of the files that end with .o (in any path). Note that shell pathname expansion has been inhibited with backslashes, so that zip can see the asterisks, enabling zip to match on the contents of the zip archive instead of the contents of the current directory.

Under MSDOS, -d is case sensitive when it matches names in the zip archive. This requires that file names be entered in upper case if they were zipped by PKZIP on an MSDOS system.

-df

[MacOS] Include only data-fork of files zipped into the archive. Good for exporting files to foreign operating-systems. Resource-forks will be ignored at all.

-D

Do not create entries in the zip archive for directories. Directory entries are created by default so that their attributes can be saved in the zip archive. The environment variable ZIPOPT can be used to change the default options. For example under Unix with sh:

ZIPOPT="-D"; export ZIPOPT

(The variable ZIPOPT can be used for any option except -i and -x and can include several options.) The option -D is a shorthand for -x "*/" but the latter cannot be set as default in the ZIPOPT environment variable.

-e

Encrypt the contents of the zip archive using a password which is entered on the terminal in response to a prompt (this will not be echoed; if standard error is not a tty, zip will exit with an error). The password prompt is repeated to save the user from typing errors.

-E

[OS/2] Use the .LONGNAME Extended Attribute (if found) as filename.

-f

Replace (freshen) an existing entry in the zip archive only if it has been modified more recently than the version already in the zip archive; unlike the update option (-u) this will not add files that are not already in the zip archive. For example:

zip -f foo

This command should be run from the same directory from which the original zip command was run, since paths stored in zip archives are always relative.

Note that the timezone environment variable TZ should be set according to the local timezone in order for the -f , -u and -o options to work correctly.

The reasons behind this are somewhat subtle but have to do with the differences between the Unix-format file times (always in GMT) and most of the other operating systems (always local time) and the necessity to compare the two. A typical TZ value is “MET-1MEST” (Middle European time with automatic adjustment for “summertime” or Daylight Savings Time).

-F

Fix the zip archive. This option can be used if some portions of the archive are missing. It is not guaranteed to work, so you MUST make a backup of the original archive first.

When doubled as in -FF the compressed sizes given inside the damaged archive are not trusted and zip scans for special signatures to identify the limits between the archive members. The single -F is more reliable if the archive is not too much damaged, for example if it has only been truncated, so try this option first.

Neither option will recover archives that have been incorrectly transferred in ascii mode instead of binary. After the repair, the -t option of unzip may show that some files have a bad CRC. Such files cannot be recovered; you can remove them from the archive using the -d option of zip.

-g

Grow (append to) the specified zip archive, instead of creating a new one. If this operation fails, zip attempts to restore the archive to its original state. If the restoration fails, the archive might become corrupted. This option is ignored when there’s no existing archive or when at least one archive member must be updated or deleted.

-h

Display the zip help information (this also appears if zip is run with no arguments).

-i files

Include only the specified files, as in:

zip -r foo . -i \*.c

which will include only the files that end in .c in the current directory and its subdirectories. (Note for PKZIP users: the equivalent command is

pkzip -rP foo *.c

PKZIP does not allow recursion in directories other than the current one.) The backslash avoids the shell filename substitution, so that the name matching is performed by zip at all directory levels.

Also possible:

zip -r foo . -i@include.lst

which will only include the files in the current directory and its subdirectories that match the patterns in the file include.lst.

-I

[Acorn RISC OS] Don’t scan through Image files. When used, zip will not consider Image files (eg. DOS partitions or Spark archives when SparkFS is loaded) as directories but will store them as single files.

For example, if you have SparkFS loaded, zipping a Spark archive will result in a zipfile containing a directory (and its content) while using the ‘I’ option will result in a zipfile containing a Spark archive. Obviously this second case will also be obtained (without the ‘I’ option) if SparkFS isn’t loaded.

-j

Store just the name of a saved file (junk the path), and do not store directory names. By default, zip will store the full path (relative to the current path).

-jj

[MacOS] record Fullpath (+ Volname). The complete path including volume will be stored. By default the relative path will be stored.

-J

Strip any prepended data (e.g. a SFX stub) from the archive.

-k

Attempt to convert the names and paths to conform to MSDOS, store only the MSDOS attribute (just the user write attribute from UNIX), and mark the entry as made under MSDOS (even though it was not); for compatibility with PKUNZIP under MSDOS which cannot handle certain names such as those with two dots.

-l

Translate the Unix end-of-line character LF into the MSDOS convention CR LF. This option should not be used on binary files. This option can be used on Unix if the zip file is intended for PKUNZIP under MSDOS. If the input files already contain CR LF, this option adds an extra CR. This ensure that unzip -a on Unix will get back an exact copy of the original file, to undo the effect of zip -l.

-ll

Translate the MSDOS end-of-line CR LF into Unix LF. This option should not be used on binary files. This option can be used on MSDOS if the zip file is intended for unzip under Unix.

-L

Display the zip license.

-m

Move the specified files into the zip archive; actually, this deletes the target directories/files after making the specified zip archive. If a directory becomes empty after removal of the files, the directory is also removed. No deletions are done until zip has created the archive without error. This is useful for conserving disk space, but is potentially dangerous so it is recommended to use it in combination with -T to test the archive before removing all input files.

-n suffixes

Do not attempt to compress files named with the given suffixes. Such files are simply stored (0% compression) in the output zip file, so that zip doesn’t waste its time trying to compress them. The suffixes are separated by either colons or semicolons. For example:

zip -rn .Z:.zip:.tiff:.gif:.snd foo foo

will copy everything from foo into foo.zip, but will store any files that end in .Z, .zip, .tiff, .gif, or .snd without trying to compress them (image and sound files often have their own specialized compression methods). By default, zip does not compress files with extensions in the list .Z:.zip:.zoo:.arc:.lzh:.arj. Such files are stored directly in the output archive. The environment variable ZIPOPT can be used to change the default options. For example under Unix with csh:

setenv ZIPOPT "-n .gif:.zip"

To attempt compression on all files, use:

zip -n : foo

The maximum compression option -9 also attempts compression on all files regardless of extension.

On Acorn RISC OS systems the suffixes are actually filetypes (3 hex digit format). By default, zip does not compress files with filetypes in the list DDC:D96:68E (i.e. Archives, CFS files and PackDir files).

-N

[Amiga, MacOS] Save Amiga or MacOS filenotes as zipfile comments. They can be restored by using the -N option of unzip. If -c is used also, you are prompted for comments only for those files that do not have filenotes.

-o

Set the "last modified" time of the zip archive to the latest (oldest) "last modified" time found among the entries in the zip archive. This can be used without any other operations, if desired. For example:

zip -o foo

will change the last modified time of foo.zip to the latest time of the entries in foo.zip.

-P password

use password to encrypt zipfile entries (if any). THIS IS INSECURE! Many multi-user operating systems provide ways for any user to see the current command line of any other user; even on stand-alone systems there is always the threat of over-the-shoulder peeking. Storing the plaintext password as part of a command line in an automated script is even worse. Whenever possible, use the non-echoing, interactive prompt to enter passwords. (And where security is truly important, use strong encryption such as Pretty Good Privacy instead of the relatively weak encryption provided by standard zipfile utilities.)

-q

Quiet mode; eliminate informational messages and comment prompts. (Useful, for example, in shell scripts and background tasks).

-Qn

[QDOS] store information about the file in the file header with n defined as

bit 0: Don’t add headers for any file

bit 1: Add headers for all files

bit 2: Don’t wait for interactive key press on exit

-r

Travel the directory structure recursively; for example:

zip -r foo foo

In this case, all the files and directories in foo are saved in a zip archive named foo.zip, including files with names starting with ".", since the recursion does not use the shell’s file-name substitution mechanism. If you wish to include only a specific subset of the files in directory foo and its subdirectories, use the -i option to specify the pattern of files to be included. You should not use -r with the name ".*", since that matches ".." which will attempt to zip up the parent directory (probably not what was intended).

-R

Travel the directory structure recursively starting at the current directory; for example:

zip -R foo ‘*.c’

In this case, all the files matching *.c in the tree starting at the current directory are stored into a zip archive named foo.zip. Note for PKZIP users: the equivalent command is

pkzip -rP foo *.c

-S

[MSDOS, OS/2, WIN32 and ATARI] Include system and hidden files.

[MacOS] Includes finder invisible files, which are ignored otherwise.

-t mmddyyyy

Do not operate on files modified prior to the specified date, where mm is the month (0-12), dd is the day of the month (1-31), and yyyy is the year. The ISO 8601 date format yyyy-mm-dd is also accepted. For example:

zip -rt 12071991 infamy foo

zip -rt 1991-12-07 infamy foo

will add all the files in foo and its subdirectories that were last modified on or after 7 December 1991, to the zip archive infamy.zip.

-tt mmddyyyy

Do not operate on files modified after or at the specified date, where mm is the month (0-12), dd is the day of the month (1-31), and yyyy is the year. The ISO 8601 date format yyyy-mm-dd is also accepted. For example:

zip -rtt 11301995 infamy foo

zip -rtt 1995-11-30 infamy foo

will add all the files in foo and its subdirectories that were last modified before the 30 November 1995, to the zip archive infamy.zip.

-T

Test the integrity of the new zip file. If the check fails, the old zip file is unchanged and (with the -m option) no input files are removed.

-u

Replace (update) an existing entry in the zip archive only if it has been modified more recently than the version already in the zip archive. For example:

zip -u stuff *

will add any new files in the current directory, and update any files which have been modified since the zip archive stuff.zip was last created/modified (note that zip will not try to pack stuff.zip into itself when you do this).

Note that the -u option with no arguments acts like the -f (freshen) option.

-v

Verbose mode or print diagnostic version info.

Normally, when applied to real operations, this option enables the display of a progress indicator during compression and requests verbose diagnostic info about zipfile structure oddities.

When -v is the only command line argument, and stdout is not redirected to a file, a diagnostic screen is printed. In addition to the help screen header with program name, version, and release date, some pointers to the Info-ZIP home and distribution sites are given. Then, it shows information about the target environment (compiler type and version, OS version, compilation date and the enabled optional features used to create the zip executable.

-V

[VMS] Save VMS file attributes. zip archives created with this option will generally not be usable on other systems.

-w

[VMS] Append the version number of the files to the name, including multiple versions of files. (default: use only the most recent version of a specified file).

-x files

Explicitly exclude the specified files, as in:

zip -r foo foo -x \*.o

which will include the contents of foo in foo.zip while excluding all the files that end in .o. The backslash avoids the shell filename substitution, so that the name matching is performed by zip at all directory levels.

Also possible:

zip -r foo foo -x@exclude.lst

which will include the contents of foo in foo.zip while excluding all the files that match the patterns in the file exclude.lst.

-X

Do not save extra file attributes (Extended Attributes on OS/2, uid/gid and file times on Unix).

-y

Store symbolic links as such in the zip archive, instead of compressing and storing the file referred to by the link (UNIX only).

-z

Prompt for a multi-line comment for the entire zip archive. The comment is ended by a line containing just a period, or an end of file condition (^D on UNIX, ^Z on MSDOS, OS/2, and VAX/VMS). The comment can be taken from a file:

zip -z foo < foowhat

-#

Regulate the speed of compression using the specified digit #, where -0 indicates no compression (store all files), -1 indicates the fastest compression method (less compression) and -9 indicates the slowest compression method (optimal compression, ignores the suffix list). The default compression level is -6.

-!

[WIN32] Use priviliges (if granted) to obtain all aspects of WinNT security.

-@

Take the list of input files from standard input. Only one filename per line.

-$

[MSDOS, OS/2, WIN32] Include the volume label for the the drive holding the first file to be compressed. If you want to include only the volume label or to force a specific drive, use the drive name as first file name, as in:

zip -$ foo a: c:bar

EXAMPLES

The simplest example:

zip stuff *

creates the archive stuff.zip (assuming it does not exist) and puts all the files in the current directory in it, in compressed form (the .zip suffix is added automatically, unless that archive name given contains a dot already; this allows the explicit specification of other suffixes).

Because of the way the shell does filename substitution, files starting with "." are not included; to include these as well:

zip stuff .* *

Even this will not include any subdirectories from the current directory.

To zip up an entire directory, the command:

zip -r foo foo

creates the archive foo.zip, containing all the files and directories in the directory foo that is contained within the current directory.

You may want to make a zip archive that contains the files in foo, without recording the directory name, foo. You can use the -j option to leave off the paths, as in:

zip -j foo foo/*

If you are short on disk space, you might not have enough room to hold both the original directory and the corresponding compressed zip archive. In this case, you can create the archive in steps using the -m option. If foo contains the subdirectories tom, dick, and harry, you can:

zip -rm foo foo/tom
zip -rm foo foo/dick
zip -rm foo foo/harry

where the first command creates foo.zip, and the next two add to it. At the completion of each zip command, the last created archive is deleted, making room for the next zip command to function.

PATTERN MATCHING

This section applies only to UNIX. Watch this space for details on MSDOS and VMS operation.

The UNIX shells (sh(1) and csh(1)) do filename substitution on command arguments. The special characters are:

?

match any single character

*

match any number of characters (including none)

[]

match any character in the range indicated within the brackets (example: [a-f], [0-9]).

When these characters are encountered (without being escaped with a backslash or quotes), the shell will look for files relative to the current path that match the pattern, and replace the argument with a list of the names that matched.

The zip program can do the same matching on names that are in the zip archive being modified or, in the case of the -x (exclude) or -i (include) options, on the list of files to be operated on, by using backslashes or quotes to tell the shell not to do the name expansion. In general, when zip encounters a name in the list of files to do, it first looks for the name in the file system. If it finds it, it then adds it to the list of files to do. If it does not find it, it looks for the name in the zip archive being modified (if it exists), using the pattern matching characters described above, if present. For each match, it will add that name to the list of files to be processed, unless this name matches one given with the -x option, or does not match any name given with the -i option.

The pattern matching includes the path, and so patterns like \*.o match names that end in ".o", no matter what the path prefix is. Note that the backslash must precede every special character (i.e. ?*[]), or the entire argument must be enclosed in double quotes ("").

In general, use backslash to make zip do the pattern matching with the -f (freshen) and -d (delete) options, and sometimes after the -x (exclude) option when used with an appropriate operation (add, -u, -f, or -d).

 

Source: http://www.computerhope.com/unix/urmdir.htm

 

About rmdir

Deletes a directory.

Syntax

rmdir [OPTION]… DIRECTORY…

–ignore-fail-on-non-empty
ignore each failure that is solely because a directory is non-empty.

-p, –parents
Remove DIRECTORY and its ancestors. E.g., `rmdir -p a/b/c’ is similar to `rmdir a/b/c a/b a’.

-v, –verbose
output a diagnostic for every directory processed.

–version
output version information and exit.

Examples

rmdir mydir – removes the directory mydir

rm -r directory – would remove a directory, even if files existed in that directory.

Related commands

rm

 

Source: http://www.computerhope.com/unix/urm.htm

 

About rm

Deletes a file without confirmation (by default).

Syntax

rm [-f] [-i] [-R] [-r] [filenames | directory]

-f
Remove all files (whether write-protected or not) in a directory without prompting the user. In a write-protected directory, however, files are never removed (whatever their permissions are), but no messages are displayed. If the removal of a write-protected directory is attempted, this option will not suppress an error message.

-i
Interactive. With this option, rm prompts for confirmation before removing any files. It over- rides the -f option and remains in effect even if the standard input is not a terminal.

-R
Same as -r option.

-r
Recursively remove directories and subdirectories in the argument list. The directory will be emptied of files and removed. The user is normally prompted for removal of any write-protected files which the directory contains. The write-protected files are removed without prompting, however, if the -f option is used, or if the standard input is not a terminal and the -i option is not used.  Symbolic links that are encountered with this option will not be traversed.  If the removal of a non-empty, write-protected directory is attempted, the utility will always fail (even if the -f option is used), resulting in an error message.

filenames
A path of a filename to be removed.

Examples

rm myfile.txt

Remove the file myfile.txt without prompting the user.

rm -r directory

Remove a directory, even if files existed in that directory.  

Note that if you use rm to remove a file, it is usually possible to recover the contents of that file. If you want more assurance that the contents are truly unrecoverable, consider using shred.

 

Source: http://www.computerhope.com/unix/shred.htm

 

About shred

Delete a file securely, first overwriting it to hide its contents.

Syntax

shred [OPTIONS] FILE [...]

-f, –force
Change permissions to allow writing if necessary.

-n, –iterations=N
Overwrite N times instead of the default (25)

-s, –size=N
shred this many bytes (suffixes like K, M, G accepted)

-u, –remove
truncate and remove file after overwriting

-v, –verbose
show progress

-x, –exact
do not round file sizes up to the next full block; this is the default for non-regular files

-z, –zero
add a final overwrite with zeros to hide shredding

-
shred standard output

–help
display this help and exit

–version
output version information and exit

Examples

shred myfile.txt

Permanently deleted and makes the file myfile.txt unrecoverable (unless stored elsewhere or on a backup).

Network Cable Color Code Standards

 

COLOR-CODE STANDARDS
Last updated: 8/9/2004

 

Again, please bear with me…  Let’s start with simple pin-out diagrams of the two types of UTP Ethernet cables and watch how committees can make a can of worms out of them.  Here are the diagrams:

 

 

Note that the TX (transmitter) pins are connected to corresponding RX (receiver) pins, plus to plus and minus to minus.  And that  you must use a crossover cable to connect units with identical interfaces.  If you use a straight-through cable, one of the two units must, in effect, perform the cross-over function.

Two wire color-code standards apply: EIA/TIA 568A and EIA/TIA 568B. The codes are commonly depicted with RJ-45 jacks as follows (the view is from the front of the jacks):

 

 

 

If we apply the 568A color code and show all eight wires, our pin-out looks like this:

 

 

Note that pins 4, 5, 7, and 8 and the blue and brown pairs are not used in either standard.  Quite contrary to what you may read elsewhere, these pins and wires are not used or required to implement 100BASE-TX duplexing–they are just plain wasted.

However, the actual cables are not physically that simple.  In the diagrams, the orange pair of wires are not adjacent.  The blue pair is upside-down.  The right ends match RJ-45 jacks and the left ends do not.  If, for example, we invert the left side of the 568A "straight"-thru cable to match a 568A jack–put one 180° twist in the entire cable from end-to-end–and twist together and rearrange the appropriate pairs, we get the following can-of-worms:

 

 

This further emphasizes, I hope,  the importance of the word "twist" in making network cables which will work.  You cannot use an flat-untwisted telephone cable for a network cable.  Furthermore, you must use a pair of twisted wires to connect a set of transmitter pins to their corresponding receiver pins.  You cannot use a wire from one pair and another wire from a different pair.

Keeping the above principles in mind, we can simplify the diagram for a 568A straight-thru cable by untwisting  the wires, except the 180° twist in the entire cable, and bending the ends upward.  Likewise, if we exchange the green and orange pairs in the 568A diagram we will get a simplified diagram for a 568B straight-thru cable.  If we cross the green and orange pairs in the 568A diagram we will arrive at a simplified diagram for a crossover cable.  All three are shown below.

 

Creating backup of your outlook data and email account settings is as essential as creating backup of any data. This will help you in case of data loss or migrating from one system to other. In Outlook 2007 your e-mails are saved in a Personal Folder File with a .pst extension which does not include in your normal backup operation. Following these simple steps can help you to save and restore your e-mail, contacts, rules, task and more.

Backup your Email data – Microsoft Outlook 2007

1. The data is saved in a Personal Folder File (.pst) only if you are not using Microsoft Exchange account or Windows Live Mail account. For Microsoft Exchange Account or Windows Live Mail account your backup data is saved locally on your computer instead of the e-mail server.          

There are two .pst files, one is the personal folder file which includes all of your Outlook folders, such as the Inbox, Calendar, tasks and Contacts and the other is the Archive Folder which includes archive messages of your Outlook.

2. You can easily locate the data files in outlook 2007 using the following steps.

Go to Main Menu of Outlook 2007, Click File and select Data File Management and Account setting window will pop up. The other way is to click on Tools menu and select Account settings from the drop down menu.

3. Click on the Data Files tab. You may have a single data file or multiple data files. These are the Data Files, wherein you store your email messages, tasks, calendar, tasks and other items. 

4. Click on the Open Folder icon. Windows Explorer will be opened automatically and will take you to the location where this data file is stored. Now select the outlook.pst and archive.pst file you want to backup.

5. Now you can copy this file to any backup storage device. Make sure that your Outlook is closed before you backup these files.

Restore your Email data – Outlook 2007

Restoring is as simple as to backup your data.  All you have to do is copy the backup PST files into the folder that you located when you backed up your work initially.

Backup/Export Account Settings – Outlook 2007

1. Start > Run > type ‘regedit’
2. Locate the following path in your ‘Registry Editor’
3. HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\Outlook

Now right click on the key outlook and select option: Export and save .pst files to your desired location. You can run the same file while restoring your outlook. This will restore your old outlook profile with all your email accounts settings and rules. You will need to enter your password as Password is not stored into .pst file.

It is difficult to locate the Personal folder files in the previous versions of Outlook; however it’s much simpler in Outlook 2007. Backing up and restoring data is easier, faster with the new outlook 2007.

 

The following is a list of locations where Microsoft Office Outlook 2007 saves information.

Some of the folders might be hidden folders. To display hidden folders, do the following:

• Windows Vista
  1. In Windows, click the Start button, and then click Control Panel.
  2. Click Appearance and Personalization.

Note   If you are using Control Panel Classic View, double-click Folder Options, and then continue with step 4.

1. Click Folder Options.
2. On the View tab, under Advanced settings, under Files and Folders, under Hidden files and folders, select Show hidden files and folders.
• Microsoft Windows XP
  1. Click the Start button, and then click Control Panel.
  2. Click Folder Options.

1. Click the View tab, and then click the Show hidden files and folders option.

Your configuration may not include all of the following files. Some files are created only when you customize Outlook features.

Personal Folders file (.pst)

Personal Folders files (.pst) contain your e-mail messages, calendars, contacts, tasks, and notes. You must use Outlook to work with the items in a .pst file.

When you archive Outlook information, items are saved in a .pst files.

Note   Microsoft Exchange Server accounts store your information on the mail server. For Cached Exchange Mode or to work offline, copies of your items are saved in an Offline Folders file (.ost). See the Offline Folders file (.ost) section for more information. Also, some organizations allow you to export or archive your items to a .pst file.

Windows Vista drive:\user\AppData\Local\Microsoft\Outlook

Microsoft Windows XP or Microsoft Windows Server 2003 drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook

Offline Folders file (.ost)

The .ost file is synchronized with the items on the server running Microsoft Exchange. Because your data remains on the Exchange server, you can recreate this .ost file on your new computer without having to back up the .ost file.

Windows Vista drive:\user\AppData\Local\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook

Personal Address Book (.pab)

Windows Vista drive:\user\AppData\Local\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook

Note   Personal Address Books (.pab) are no longer supported by Office Outlook 2007. When you upgrade to Office Outlook 2007, you are prompted to import any .pab file into Contacts. If you choose not to import the .pab file, you can import it later by using the Import and Export command on the File menu.

Offline Address Book (.oab)

The Office Address Book (.oab) is used by Microsoft Exchange Server accounts. The Offline Address Book contains the properties of a user, such as e-mail addresses, that Outlook requires in order to send an e-mail message and display information about the user. By using the Offline Address Book, Outlook does not have to connect to Exchange in order to resolve names or open the records for each user. This reduces network traffic and improves performance.

You do not need to back up or restore this file. This is file is created and updated by Outlook.

Windows Vista drive:\user\AppData\Local\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook

Command bar and menu customizations (.dat)

Windows Vista drive:\user\AppData\Roaming\Microsoft\Outlook\outcmd.dat

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Outlook\outcmd.dat

Navigation Pane settings (.xml)

Windows Vista drive:\user\AppData\Roaming\Outlook\profile name.xml

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Outlook\profile name.xml

This file includes Shortcuts, Calendar, and Contact links.

Registered Microsoft Exchange extensions (.dat)

Windows Vista drive:\user\AppData\Local\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook

Outlook Contacts AutoComplete (.nk2)

AutoComplete is a feature which displays suggestions for names and e-mail addresses as you begin to type them. These suggestions are possible matches from a list of names and e-mail addresses that you have typed before, known as the AutoComplete name list.

Windows Vista drive:\user\AppData\Roaming\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Outlook

Rules (.rwz)

Windows Vista drive:\<user\AppData\Roaming\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Outlook

Note   If you upgraded to Office Outlook 2007 from a version of Outlook earlier than Microsoft Outlook 2002, you might have an .rwz file on your computer’s hard disk drive. The .rwz file is no longer needed, and the information about rules is now kept on the server running Microsoft Exchange, and in the Personal Folders file (.pst) (Personal Folders file (.pst): Data file that stores your messages and other items on your computer. You can assign a .pst file to be the default delivery location for e-mail messages. You can use a .pst to organize and back up items for safekeeping.) for POP3 (POP3: A common protocol that is used to retrieve e-mail messages from an Internet e-mail server.) and IMAP (IMAP (Internet Message Access Protocol): Unlike Internet e-mail protocols such as POP3, IMAP creates folders on a server to store/organize messages for retrieval by other computers. You can read message headers only and select which messages to download.) e-mail accounts. So you can delete the file.

If you use the Rules Import and Export feature, the default location for .rwz files is drive:\Documents and Settings\user\My Documents.

Print styles (Outlprnt with no extension)

Windows Vista drive:\user\AppData\Roaming\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Outlook

Signatures (.rtf, .txt, .htm)

Windows Vista drive:\user\AppData\Roaming\Microsoft\Signatures

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Signatures

Stationery (.htm)

Windows Vista drive:\Program Files\Common Files\Microsoft Shared\Stationery

Windows XP or Windows Server 2003 drive:\Program Files\Common Files\Microsoft Shared\Stationery

Custom forms

Windows Vista drive:\user\AppData\Local\Microsoft\Forms

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Forms

Dictionary (.dic)

Windows Vista drive:\user\AppData\Roaming\Microsoft\UProof

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\UProof

Templates (.oft)

Windows Vista drive:\user\AppData\Roaming\Microsoft\Templates

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Templates

Send/Receive settings (.srs)

Windows Vista drive:\user\AppData\Roaming\Microsoft\Outlook

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\Application Data\Microsoft\Outlook

Message (.msg, .htm, .rtf)

Windows Vista drive:\user\Documents

Windows XP or Windows Server 2003 drive:\Documents and Settings\user\My Documents

• twist ((shell_command) Replace the current process by an instance of the specified
  shell command, after performing the % expansions described in the
  hosts_access(5) manual page.)
• deny (Denys Service/Access)
• banners ((/some/directory) Look for a file in "/some/directory" with the same
  name as the daemon process (for example in.telnetd for the telnet
  service), and copy its contents to the client. Newline characters are replaced
  by carriage-return newline, and % sequences are expanded (see the
  hosts_access(5) manual page).)
• nice ([number] Change the nice value of the process (default 10). Specify a positive
  value to spend more CPU resources on other processes.)
• rfc931 ([timeout_in_seconds] Look up the client user name with the RFC 931 (TAP, IDENT,
  RFC 1413) protocol. This option is silently ignored in case of services based
  on transports other than TCP. It requires that the client system runs an RFC
  931 (IDENT, etc.) -compliant daemon, and may cause noticeable delays with
  connections from non-UNIX clients. The timeout period is optional. If no
  timeout is specified a compile-time defined default value is taken.)
• setenv ((name) (value) Place a (name, value) pair into the process environment. The
  value is subjected to % expansions and may contain whitespace (but
  leading and trailing blanks are stripped off).)
• user ((user[.group]) Ammume the privleges of the user and group)
• allow (Permits Service/Access)
• umask ((umask) Like the umask command that is built into the shell. Should be octal)
• keepalive (Causes the server to periodically send a message to the client. The connection
  is considered broken when the client does not respond. The keepalive option can
  be useful when users turn off their machine while it is still connected to a
  server. The keepalive option is not useful for datagram (UDP) services.)

 

Just locate the following key in registry (start – run – regedit):

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\Outlook

Then right click on the key, outlook and select option, Export…save it anywhere you want…
and run it while restoring your outlook.

This will restore your old outlook profile with all email accounts and rules.
But, you will have to enter passwords for the accounts again. It does not store the user passwords.