Bash - how to unzip a piped zip file (from “wg

问题:

Any ideas on how to unzip a piped zip file like this:

wget -qO- http://downloads.wordpress.org/plugin/akismet.2.5.3.zip

I wished to unzip the file to a directory, like we used to do with a normal file:

wget -qO- http://downloads.wordpress.org/plugin/akismet.2.5.3.zip | unzip -d ~/Desktop

回答1:

wget -q -O tmp.zip http://downloads.wordpress.org/plugin/akismet.2.5.3.zip && unzip tmp.zip && rm tmp.zip

回答2:

The ZIP file format includes a directory (index) at the end of the archive. This directory says where, within the archive each file is located and thus allows for quick, random access, without reading the entire archive.

This would appear to pose a problem when attempting to read a ZIP archive through a pipe, in that the index is not accessed until the very end and so individual members cannot be correctly extracted until after the file has been entirely read and is no longer available. As such it appears unsurprising that most ZIP decompressors simply fail when the archive is supplied through a pipe.

The directory at the end of the archive is not the only location where file meta information is stored in the archive. In addition, individual entries also include this information in a local file header, for redundancy purposes.

Although not every ZIP decompressor will use local file headers when the index is unavailable, the tar and cpio front ends to libarchive (a.k.a. bsdtar and bsdcpio) can and will do so when reading through a pipe, meaning that the following is possible:

wget -qO- http://downloads.wordpress.org/plugin/akismet.2.5.3.zip | bsdtar -xvf- -C ~/Desktop

回答3:

While the following will not work in bash, it will work in zsh. Since many zsh users may end up here, it may still be useful:

unzip =( wget -qO- http://downloads.wordpress.org/plugin/akismet.2.5.3.zip )

回答4:

just use zcat

wget -qO- http://downloads.wordpress.org/plugin/akismet.2.5.3.zip | zcat >> myfile.txt

• This will only extract first file. You will see this error message "gzip: stdin has more than one entry--rest ignored" after the first file is extracted.

回答5:

I'd take a look at funzip (http://www.info-zip.org/mans/funzip.html). The man page for it notes,

...filter for extracting from a ZIP archive in a pipe

Sorry I don't have an example, but it looks like it does come with the Linux unzip utility.

回答6:

BusyBox's unzip can take stdin and extract all the files.

wget -qO- http://downloads.wordpress.org/plugin/akismet.2.5.3.zip | busybox unzip -

The dash after unzip is to use stdin as input.

You can even,

cat file.zip | busybox unzip -

But that's just redundant of unzip file.zip.

If your distro uses BusyBox by default (e.g. Alpine), just run unzip -.