Unzip will list, test, or extract files from a ZIP archive, commonly found on Unix systems. The default behavior (with no options) is to extract into the current directory (and sub-directories below it) all files from the specified ZIP archive.
Options :1. -d Option: Removes the file from the zip archive. After creating a zip file, you can remove a file from the archive using the -d option.Suppose we have following files in my current directory are listed below:hello1.chello2.chello3.chello4.chello5.chello6.chello7.chello8.cSyntax :
can i zip a directory in unix
3. -m Option: Deletes the original files after zipping. 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 removing all input files.Syntax :
4.-r Option: To zip a directory recursively, use the -r option with the zip command and it will recursively zips the files in a directory. This option helps you to zip all the files present in the specified directory.Syntax:
5. -x Option: Exclude the files in creating the zip. Let say you are zipping all the files in the current directory and want to exclude some unwanted files. You can exclude these unwanted files using the -x option.Syntax :
A directory is placed at the end of a ZIP file. This identifies what files are in the ZIP and identifies where in the ZIP that file is located. This allows ZIP readers to load the list of files without reading the entire ZIP archive. ZIP archives can also include extra data that is not related to the ZIP archive. This allows for a ZIP archive to be made into a self-extracting archive (application that decompresses its contained data), by prepending the program code to a ZIP archive and marking the file as executable. Storing the catalog at the end also makes possible hiding a zipped file by appending it to an innocuous file, such as a GIF image file.
A ZIP file is correctly identified by the presence of an end of central directory record which is located at the end of the archive structure in order to allow the easy appending of new files. If the end of central directory record indicates a non-empty archive, the name of each file or directory within the archive should be specified in a central directory entry, along with other metadata about the entry, and an offset into the ZIP file, pointing to the actual entry data. This allows a file listing of the archive to be performed relatively quickly, as the entire archive does not have to be read to see the list of files. The entries within the ZIP file also include this information, for redundancy, in a local file header. Because ZIP files may be appended to, only files specified in the central directory at the end of the file are valid. Scanning a ZIP file for local file headers is invalid (except in the case of corrupted archives), as the central directory may declare that some files have been deleted and other files have been updated.
For example, we may start with a ZIP file that contains files A, B and C. File B is then deleted and C updated. This may be achieved by just appending a new file C to the end of the original ZIP file and adding a new central directory that only lists file A and the new file C. When ZIP was first designed, transferring files by floppy disk was common, yet writing to disks was very time-consuming. If you had a large zip file, possibly spanning multiple disks, and only needed to update a few files, rather than reading and re-writing all the files, it would be substantially faster to just read the old central directory, append the new files then append an updated central directory.
The ZIP format uses specific 4-byte "signatures" to denote the various structures in the file. Each file entry is marked by a specific signature. The end of central directory record is indicated with its specific signature, and each entry in the central directory starts with the 4-byte central file header signature.
Tools that correctly read ZIP archives must scan for the end of central directory record signature, and then, as appropriate, the other, indicated, central directory records. They must not scan for entries from the top of the ZIP file, because (as previously mentioned in this section) only the central directory specifies where a file chunk starts and that it has not been deleted. Scanning could lead to false positives, as the format does not forbid other data to be between chunks, nor file data streams from containing such signatures. However, tools that attempt to recover data from damaged ZIP archives will most likely scan the archive for local file header signatures; this is made more difficult by the fact that the compressed size of a file chunk may be stored after the file chunk, making sequential processing difficult.
This ordering allows a ZIP file to be created in one pass, but the central directory is also placed at the end of the file in order to facilitate easy removal of files from multiple-part (e.g. "multiple floppy-disk") archives, as previously discussed.
The original .ZIP format had a 4 GB (232 bytes) limit on various things (uncompressed size of a file, compressed size of a file, and total size of the archive), as well as a limit of 65,535 (216-1) entries in a ZIP archive. In version 4.5 of the specification (which is not the same as v4.5 of any particular tool), PKWARE introduced the "ZIP64" format extensions to get around these limitations, increasing the limits to 16 EB (264 bytes). In essence, it uses a "normal" central directory entry for a file, followed by an optional "zip64" directory entry, which has the larger fields.[39]
The format of the Local file header (LOC) and Central directory entry (CEN) are the same in ZIP and ZIP64. However, ZIP64 specifies an extra field that may be added to those records at the discretion of the compressor, whose purpose is to store values that do not fit in the classic LOC or CEN records. To signal that the actual values are stored in ZIP64 extra fields, they are set to 0xFFFF or 0xFFFFFFFF in the corresponding LOC or CEN record. If one entry does not fit into the classic LOC or CEN record, only that entry is required to be moved into a ZIP64 extra field. The other entries may stay in the classic record. Therefore, not all entries shown in the following table might be stored in a ZIP64 extra field. However, if they appear, their order must be as shown in the table.
To work around this, copy the reader package to an external directory called realpython/ and place the __main__.py file at its root. Then remove the __pycache__/ folder that results from running python -m reader, which you did before. You should end up with the following directory structure:
To showcase the -m and --main command-line options of zipapp, say you decide to change the reader project layout and rename __main__.py to cli.py while moving the file back to the reader package. Go ahead and create a copy of your realpython/ directory and make the suggested changes. After that, the copy of realpython/ should look like this:
The code below shows how to create the reader Zip application using zipfile.ZipFile and a few other tools. For example, the code relies on pathlib and stat to read the contents of the source directory and set execution permission to the resulting file:
In this example, you first cd into the realpython/ directory. Then you zip the contents of realpython/ into realpython.zip using the zip command with the -r option. This option recursively traverses the target directory.
The --create command-line option of zipfile allows you to create a ZIP file from a source directory. The asterisk (*) appended to the realpython/ directory tells zipfile to put the contents of that directory at the root of the resulting ZIP file.
This command creates realpython.pex in your current directory. This file is a Python executable for reader. Note that pex handles the installations of reader and all its dependencies from PyPI. The reader project is available on PyPI with the name realpython-reader, which is why you use that name as the first argument to pex.
To build a Python Zip application with shiv, you need an installable Python application with a setup.py or pyproject.toml file. Fortunately, the original reader project from GitHub fulfills this requirement. Go back to the directory containing the cloned reader/ folder and run the following command:
First, please create the zip folder in unix as below by using the zip command. Please go to path /sas/lsf/Eighty_Twenty/Inputs/PDF and then open the unix terminal from here and then type the below command
In some cases, you may wish to compress an entire directory, but not include certain files and directories. You can do so by appending an --exclude switch for each directory or file you want to exclude.
You may want to extract the contents of the archive to a specific directory. You can do so by appending the -C switch to the end of the command. For example, the following command will extract the contents of the archive.tar.gz file to the /tmp directory.
To add a new file to the existing ZIP file (newfiles.zip), run the following command. The command below updates (-u) the existing ZIP file package (newfiles.zip) by recursively (-r) searching through all files in the /mydir directory, then adding them to the ZIP package.
To unzip a ZIP file, launch your terminal and run the following command. Notice the command below will unzip the contents of the (newdir.zip) ZIP file. By default, the contents are extracted to the same directory (/mydir) of the (newdir.zip) ZIP file.
To demonstrate how to script some common use cases with the zip utility, perhaps you have a directory with many different files but only need to compress those that match a specific extension. To do that, you need a script that will repeatedly search for all files with the same extension. When found, adds them to a zip file. 2ff7e9595c
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