此篇博客用来分门别类地记录已经英文阅读的材料，目的是待到某一类的材料积累到一定量的时候，导入程序生成对应的词典，提高背单词的有效性。
man手册
zip
zip is a compression and file packaging utility for Unix, VMS, MSDOS, OS/2, Windows 9x/NT/XP, Minix, Atari, 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 (supporting most PKZIP features up to PKZIP version 4.6), and PKZIP and PKUNZIP can work with archives produced by zip (with some exceptions, notably streamed archives, but recent changes in the zip file standard may facilitate better compatibility). zip version 3.0 is compatible with PKZIP 2.04 and also supports the Zip64 extensions of PKZIP 4.5 which allow archives as well as files to exceed the previous 2 GB limit (4 GB in some cases). zip also now supports bzip2 compression if the bzip2 library is included when zip is compiled. Note that PKUNZIP 1.10 cannot extract files produced by PKZIP 2.04 or zip 3.0. You must use PKUNZIP 2.04g or unzip 5.0p1 (or later versions) to extract them.
See the EXAMPLES section at the bottom of this page for examples of some typical uses of zip.
Large Archives and Zip64. zip automatically uses the Zip64 extensions when files larger than 4 GB are added to an archive, an archive containing Zip64 entries is updated (if the resulting archive still needs Zip64), the size of the archive will exceed 4 GB, or when the number of entries in the archive will exceed about 64K. Zip64 is also used for archives streamed from standard input as the size of such archives are not known in advance, but the option -fz- can be used to force zip to create PKZIP 2 compatible archives (as long as Zip64 extensions are not needed). You must use a PKZIP 4.5 compatible unzip, such as unzip 6.0 or later, to extract files using the Zip64 extensions.
In addition, streamed archives, entries encrypted with standard encryption, or split archives created with the pause option may not be compatible with PKZIP as data descriptors are used and PKZIP at the time of this writing does not support data descriptors (but recent changes in the PKWare published zip standard now include some support for the data descriptor format zip uses).
Mac OS X. Though previous Mac versions had their own zip port, zip supports Mac OS X as part of the Unix port and most Unix features apply. References to "MacOS" below generally refer to MacOS versions older than OS X. Support for some Mac OS features in the Unix Mac OS X port, such as resource forks, is expected in the next zip release.
For a brief help on zip and unzip, run each without specifying any parameters on the command line.
Use
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. (If bzip2 support is added, zip can also compress using bzip2 compression, but such entries require a reasonably modern unzip to decompress. When bzip2 compression is selected, it replaces deflation as the default method.) zip automatically chooses the better of the two (deflation or store or, if bzip2 is selected, bzip2 or store) for each file to be compressed.
Command format. The basic command format is
zip options archive inpath inpath ...
where archive is a new or existing zip archive and inpath is a directory or file path optionally including wildcards. When given the name of an existing zip archive, zip will replace identically named entries in the zip archive (matching the relative names as stored in the 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.zip foo
or more concisely
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.
So if before the zip command is executed foo.zip has:
foo/file1 foo/file2
and directory foo has:
file1 file3
then foo.zip will have:
foo/file1 foo/file2 foo/file3
where foo/file1 is replaced and foo/file3 is new.
github
pyenv
How It Works
At a high level, pyenv intercepts Python commands using shim executables injected into your PATH, determines which Python version has been specified by your application, and passes your commands along to the correct Python installation.
Understanding PATH
When you run a command like python or pip, your operating system searches through a list of directories to find an executable file with that name. This list of directories lives in an environment variable called PATH, with each directory in the list separated by a colon:
/usr/local/bin:/usr/bin:/bin
Directories in PATH are searched from left to right, so a matching executable in a directory at the beginning of the list takes precedence over another one at the end. In this example, the /usr/local/bin directory will be searched first, then /usr/bin, then /bin.
Understanding Shims
pyenv works by inserting a directory of shims at the front of your PATH:
$(pyenv root)/shims:/usr/local/bin:/usr/bin:/bin
Through a process called rehashing, pyenv maintains shims in that directory to match every Python command across every installed version of Python—python, pip, and so on.
Shims are lightweight executables that simply pass your command along to pyenv. So with pyenv installed, when you run, say, pip, your operating system will do the following:
Search your PATH for an executable file named pip
Find the pyenv shim named pip at the beginning of your PATH
Run the shim named pip, which in turn passes the command along to pyenv