tar cjvf C.tar.bz2 B # 默认是在当前文件夹下的
OK后会在/A文件夹下有个名为“C.tar.bz2”的tar压缩文件
tar tvf C.tar.bz2 # 列出里面的文件
会用了吧？ 呵呵 再把文档粘给你 比较长 别哭哦 学习之路还很远的
TAR(1)tar TAR(1)
NAME
tar - The GNU version of the tar archiving utility
SYNOPSIS
tar <operation>[options]
Operations:
[-]A --catenate --concatenate
[-]c --create
[-]d --diff --compare
[-]r --append
[-]t --list
[-]u --update
[-]x --extract --get
--delete
Common Options:
-C, --directory DIR
-f, --file F
-j, --bzip2
-p, --preserve-permissions
-v, --verbose
-z, --gzip
All Options:
[ --atime-preserve ] [ -b, --blocking-factor N ] [ -B, --read-full-
records ] [ --backup BACKUP-TYPE ] [ --block-compress ] [ -C, --direc-
tory DIR ] [ --check-links ] [ --checkpoint ] [ -f, --file [HOSTNAME:]F
] [ -F, --info-script F --new-volume-script F ] [ --force-local] [
--format FORMAT ] [ -g, --listed-incremental F ] [ -G, --incremental ]
[ --group GROUP ] [ -h, --dereference ] [ --help ] [ -i, --ignore-zeros
] [ --ignore-case ] [ --ignore-failed-read ] [ --index-file FILE ] [
-j, --bzip2 ] [ -k, --keep-old-files ] [ -K, --starting-file F ] [
--keep-newer-files ] [ -l, --one-file-system ] [ -L, --tape-length N ]
[ -m, --touch, --modification-time ] [ -M, --multi-volume ] [ --mode
PERMISSIONS ] [ -N, --after-date DATE, --newer DATE ] [ --newer-mtime
DATE ] [ --no-anchored ] [ --no-ignore-case ] [ --no-recursion ] [
--no-same-permissions ] [ --no-wildcards ] [ --no-wildcards-match-slash
] [ --null ] [ --numeric-owner ] [ -o, --old-archive, --portabil-
ity, --no-same-owner ] [ -O, --to-stdout ] [ --occurrence NUM ] [
--overwrite ] [ --overwrite-dir ] [ --owner USER ] [ -p, --same-permis-
sions, --preserve-permissions ] [ -P, --absolute-names ] [ --pax-option
KEYWORD-LIST ] [ --posix ] [ --preserve ] [ --acls ] [ --selinux ] [
--xattrs ] [ --no-acls ] [ --no-selinux ] [ --no-xattrs ] [ -R,
--block-number ] [ --record-size SIZE ] [ --recursion ] [ --recursive-
unlink ] [ --remove-files ] [ --rmt-command CMD ] [ --rsh-command CMD ]
[ -s, --same-order, --preserve-order ] [ -S, --sparse ] [ --same-owner
] [ --show-defaults ] [ --show-omitted-dirs ] [ --strip-components NUM-
BER, --strip-path NUMBER (1) ] [ --suffix SUFFIX ] [ -T, --files-from F
] [ --totals ] [ -U, --unlink-first ] [ --use-compress-program PROG ]
[ --utc ] [ -v, --verbose ] [ -V, --label NAME ] [ --version ] [
--volno-file F ] [ -w, --interactive, --confirmation ] [ -W, --verify ]
[ --wildcards ] [ --wildcards-match-slash ] [ --exclude PATTERN ] [ -X,
--exclude-from FILE ] [ -Z, --compress, --uncompress ] [ -z, --gzip,
--gunzip, --ungzip ] [ -[0-7][lmh] ]
(1) tar-1.14 uses --strip-path, tar-1.14.90+ uses --strip-components
DESCRIPTION
This manual page documents the GNU version of tar, an archiving program
designed to store and extract files from an archive file known as a
tarfile. A tarfile may be made on a tape drive, however, it is also
common to write a tarfile to a normal file. The first argument to tar
must be one of the options Acdrtux, followed by any optional functions.
The final arguments to tar are the names of the files or directories
which should be archived. The use of a directory name always implies
that the subdirectories below should be included in the archive.
EXAMPLES
tar -xvf foo.tar
verbosely extract foo.tar
tar -xzf foo.tar.gz
extract gzipped foo.tar.gz
tar -cjf foo.tar.bz2 bar/
create bzipped tar archive of the directory bar called
foo.tar.bz2
tar -xjf foo.tar.bz2 -C bar/
extract bzipped foo.tar.bz2 after changing directory to bar
tar -xzf foo.tar.gz blah.txt
extract the file blah.txt from foo.tar.gz
FUNCTION LETTERS
One of the following options must be used:
-A, --catenate, --concatenate
append tar files to an archive
-c, --create
create a new archive
-d, --diff, --compare
find differences between archive and file system
-r, --append
append files to the end of an archive
-t, --list
list the contents of an archive
-u, --update
only append files that are newer than the existing in archive
-x, --extract, --get
extract files from an archive
--delete
delete from the archive (not for use on mag tapes!)
COMMON OPTIONS
-C, --directory DIR
change to directory DIR
-f, --file [HOSTNAME:]F
use archive file or device F (default "-", meaning stdin/stdout)
-j, --bzip2
filter archive through bzip2, use to decompress .bz2 files
-p, --preserve-permissions
extract all protection information
-v, --verbose
verbosely list files processed
-z, --gzip, --ungzip
filter the archive through gzip
ALL OPTIONS
--atime-preserve
don't change access times on dumped files
-b, --blocking-factor N
block size of Nx512 bytes (default N=20)
-B, --read-full-blocks
reblock as we read (for reading 4.2BSD pipes)
--backup BACKUP-TYPE
backup files instead of deleting them using BACKUP-TYPE simple
or numbered
--block-compress
block the output of compression program for tapes
-C, --directory DIR
change to directory DIR
--check-links
warn if number of hard links to the file on the filesystem mis-
match the number of links recorded in the archive
--checkpoint
print directory names while reading the archive
-f, --file [HOSTNAME:]F
use archive file or device F (default "-", meaning stdin/stdout)
-F, --info-script F --new-volume-script F
run script at end of each tape (implies --multi-volume)
--force-local
archive file is local even if has a colon
--format FORMAT
selects output archive format
v7 - Unix V7
oldgnu - GNU tar <=1.12
gnu - GNU tar 1.13
ustar - POSIX.1-1988
posix - POSIX.1-2001
-g, --listed-incremental F
create/list/extract new GNU-format incremental backup
-G, --incremental
create/list/extract old GNU-format incremental backup
-h, --dereference
don't dump symlinksdump the files they point to
--help like this manpage, but not as cool
-i, --ignore-zeros
ignore blocks of zeros in archive (normally mean EOF)
--ignore-case
ignore case when excluding files
--ignore-failed-read
don't exit with non-zero status on unreadable files
--index-file FILE
send verbose output to FILE instead of stdout
-j, --bzip2
filter archive through bzip2, use to decompress .bz2 files
-k, --keep-old-files
keep existing filesdon't overwrite them from archive
-K, --starting-file F
begin at file F in the archive
--keep-newer-files
do not overwrite files which are newer than the archive
-l, --one-file-system
stay in local file system when creating an archive
-L, --tape-length N
change tapes after writing N*1024 bytes
-m, --touch, --modification-time
don't extract file modified time
-M, --multi-volume
create/list/extract multi-volume archive
--mode PERMISSIONS
apply PERMISSIONS while adding files (see chmod(1))
-N, --after-date DATE, --newer DATE
only store files newer than DATE
--newer-mtime DATE
like --newer, but with a DATE
--no-anchored
match any subsequenceof the name's components with --exclude
--no-ignore-case
use case-sensitive matching with --exclude
--no-recursion
don't recurse into directories
--no-same-permissions
apply user's umask when extracting files instead of recorded
permissions
--no-wildcards
don't use wildcards with --exclude
--no-wildcards-match-slash
wildcards do not match slashes (/) with --exclude
--null --files-from reads null-terminated names, disable --directory
--numeric-owner
always use numbers for user/group names
-o, --old-archive, --portability
like --format=v7 -o exhibits this behavior when creating an
archive (deprecated behavior)
-o, --no-same-owner
do not attempt to restore ownership when extracting-o exhibits
this behavior when extracting an archive
-O, --to-stdout
extract files to standard output
--occurrence NUM
process only NUM occurrences of each named fileused with
--delete, --diff, --extract, or --list
--overwrite
overwrite existing files and directory metadata when extracting
--overwrite-dir
overwrite directory metadata when extracting
--owner USER
change owner of extraced files to USER
-p, --same-permissions, --preserve-permissions
extract all protection information
-P, --absolute-names
don't strip leading '/'s from file names
--pax-option KEYWORD-LIST
used only with POSIX.1-2001 archives to modify the way tar han-
dles extended header keywords
--posix
like --format=posix
--preserve
like --preserve-permissions --same-order
--acls this option causes tar to store each file's ACLs in the archive.
--selinux
this option causes tar to store each file's SELinux security
context information in the archive.
--xattrs
this option causes tar to store each file's extended attributes
in the archive. This option also enables --acls and--selinux if
they haven't been set already, due to the fact that the data for
those are stored in special xattrs.
--no-acls
This option causes tar not to store each file's ACLs in the
archive and not to extract any ACL information in an archive.
--no-selinux
this option causes tar not to store each file's SELinux security
context information in the archive and not to extract any
SELinux information in an archive.
--no-xattrs
this option causes tar not to store each file's extended
attributes in the archive and not to extract any extended
attributes in an archive. This option also enables --no-acls and
--no-selinux if they haven't been set already.
-R, --record-number
show record number within archive with each message
--record-size SIZE
use SIZE bytes per record when accessing archives
--recursion
recurse into directories
--recursive-unlink
remove existing directories before extracting directories of the
same name
--remove-files
remove files after adding them to the archive
--rmt-command CMD
use CMD instead of the default /usr/sbin/rmt
--rsh-command CMD
use remote CMD instead of rsh(1)
-s, --same-order, --preserve-order
list of names to extract is sorted to match archive
-S, --sparse
handle sparse files efficiently
--same-owner
create extracted files with the same ownership
--show-defaults
display the default options used by tar
--show-omitted-dirs
print directories tar skips while operating on an archive
--strip-components NUMBER, --strip-path NUMBER
strip NUMBER of leading components from file names before
extraction
(1) tar-1.14 uses --strip-path, tar-1.14.90+ uses --strip-compo-
nents
--suffix SUFFIX
use SUFFIX instead of default '~' when backing up files
-T, --files-from F
get names to extract or create from file F
--totals
print total bytes written with --create
-U, --unlink-first
remove existing files before extracting files of the same name
--use-compress-program PROG
access the archive through PROG which is generally a compression
program
--utc display file modification dates in UTC
-v, --verbose
verbosely list files processed
-V, --label NAME
create archive with volume name NAME
--version
print tar program version number
--volno-file F
keep track of which volume of a multi-volume archive its working
in FILEused with --multi-volume
-w, --interactive, --confirmation
ask for confirmation for every action
-W, --verify
attempt to verify the archive after writing it
--wildcards
use wildcards with --exclude
--wildcards-match-slash
wildcards match slashes (/) with --exclude
--exclude PATTERN
exclude files based upon PATTERN
-X, --exclude-from FILE
exclude files listed in FILE
-Z, --compress, --uncompress
filter the archive through compress
-z, --gzip, --gunzip, --ungzip
filter the archive through gzip
--use-compress-program PROG
filter the archive through PROG (which must accept -d)
-[0-7][lmh]
specify drive and density
BUGS
The GNU folks, in general, abhor man pages, and create info documents
instead. The maintainer of tar falls into this category. Thus this
man page may not be complete, nor current, and was included in the Red
Hat CVS tree because man is a great tool :). This man page was first
taken from Debian Linux and has since been loving updated here.
REPORTING BUGS
Please report bugs via https://bugzilla.redhat.com
SEE ALSO
The full documentation for tar is maintained as a Texinfo manual. If
the info and tar programs are properly installed at your site, the com-
mand
info tar
should give you access to the complete manual.
AUTHORS
Debian Linux http://www.debian.org/
Mike Frysinger [email protected]>
GNUOct 2004 TAR(1)
是指函数在运行过程中直接或间接调用自身而产生的现象.
数列就是最常见的递归现象。
如 a1 a2 a3 a4 a5 a6
1 2 6
an = a(n-1) + 1
比如要求 a6 根据公式 a6 = a5 + 1
要求a6 求a5 a5 = a4 + 1
要求a5 必先求a4 a4 = a3 + 1
直到最后求出 a1 = 1
然后还回 a2 然后 a3 然后 a4 然后 a5 然后 a6 得出结果
递归电脑计算时计算过程比较复杂，但是写的程序却很简单，比如这题
int Getan( int i){
if(i == 1) return 1
return Getan(i-1) + 1 //这里每次递归（也就是调用自己（这里是调用Getan(i-1)））
// i会递减 , 所以最后 i总会等于1， 从而结束递归
｝
/////////////////////////////////////////////
void show_number(char a,int number,int count){
if(count!=0){
for(int i(0)i!=3++i){
cout<<a
show_number(a+1,number-1,count-1) //这个地方递归 ，注意到这里实参为count-1, 在每一次进入函数时，形参count获得的值比之前少1， 所以最终能够退出递归。
cout<<number
cout<<endl
}
}
}
//你是问递归的执行顺序吗
//////////////////////////////////////
void nestedtriangle(turtle & worker, double size, int level){
if(not level) return // level 等于0时结束递归
for(int i(0) i != 3 ++i){ //每次调用3次自身
nestedtriangle(worker, size/2, level-1) //每次level-1， 所以深度为level次
worker.forward(size)
worker.left(120) //这两步调用3次后画出一个三角形
}
}
// 这里无法贴出两张图片，就用口说吧。
你先想像如果没有递归，讲画出一个边长为size的三角形，为方便叙述，设这个三角形的三个定点为ABC。 因为有了递归，而且递归3次，//注意递归在画边之前
假设level = 2；
1、在for中 ，i=0时， 调用 nestedtriangle(worker, size/2, 1), 而该函数以A为起点，size/2为边长画出一个三角形， 然后画出变AB。此时worker运动到B点
2、 i=1时，调用 nestedtriangle(worker, size/2, 1), 而该函数以B为起点，size/2为边长画出一个三角形， 然后画出变BC。此时worker运动到C点
3、 i=2时，调用 nestedtriangle(worker, size/2, 1), 而该函数以C为起点，size/2为边长画出一个三角形， 然后画出变CA。此时worker运动到A点，
4、i=3，结束调用。
从中你可以看出level=2时可以画出2层小三角形，依次类推， level=3时可以画出3层。
不懂加我QQ51321640，注明百度知道_递归
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