In this article we are going to see how we can use wget.

What is wget?

Wget stands for Web Get. Wget is a CLI utilities for HTTP, HTTPS, FTP and FTPS request in commandline . It is one of the most popular ubuntu tools used for data crawling/testing.

Why wget?

  • Ready to run without install in ubuntu systems
  • fast & easy
  • site crawling is easy
  • you can create batch crawler with wget.

Installation

  • Install via APT

       sudo apt-get update && sudo apt-get install wget       	
    

Useful Options

  • no Certificate checks

         --no-check-certificate
    
  • Turn Off following robot text

    -e robots=off
    
  • Level to download

      -l,  --level=NUMBER       maximum recursion depth (inf or 0 for infinite).
    
  • Accepted Patterns

      -A,  --accept=LIST               comma-separated list of accepted extensions.
    

Examples

  • To download whole site (http, not https)

       wget -r --no-parent _site_url
    
  • Get all Ubuntu ISO files from CDN (will be hundreds of GB)

       wget -r -l4 -A.iso http://cdimage.ubuntu.com
    

Official Manual

More Options

There are more CLI options, here is the whole list.

Startup:
  -V,  --version           display the version of Wget and exit.
  -h,  --help              print this help.
  -b,  --background        go to background after startup.
  -e,  --execute=COMMAND   execute a `.wgetrc'-style command.

Logging and input file:
  -o,  --output-file=FILE    log messages to FILE.
  -a,  --append-output=FILE  append messages to FILE.
  -d,  --debug               print lots of debugging information.
  -q,  --quiet               quiet (no output).
  -v,  --verbose             be verbose (this is the default).
  -nv, --no-verbose          turn off verboseness, without being quiet.
	   --report-speed=TYPE   Output bandwidth as TYPE.  TYPE can be bits.
  -i,  --input-file=FILE     download URLs found in local or external FILE.
  -F,  --force-html          treat input file as HTML.
  -B,  --base=URL            resolves HTML input-file links (-i -F)
							 relative to URL.
	   --config=FILE         Specify config file to use.

Download:
  -t,  --tries=NUMBER            set number of retries to NUMBER (0 unlimits).
	   --retry-connrefused       retry even if connection is refused.
  -O,  --output-document=FILE    write documents to FILE.
  -nc, --no-clobber              skip downloads that would download to
								 existing files (overwriting them).
  -c,  --continue                resume getting a partially-downloaded file.
	   --progress=TYPE           select progress gauge type.
  -N,  --timestamping            don't re-retrieve files unless newer than
								 local.
  --no-use-server-timestamps     don't set the local file's timestamp by
								 the one on the server.
  -S,  --server-response         print server response.
	   --spider                  don't download anything.
  -T,  --timeout=SECONDS         set all timeout values to SECONDS.
	   --dns-timeout=SECS        set the DNS lookup timeout to SECS.
	   --connect-timeout=SECS    set the connect timeout to SECS.
	   --read-timeout=SECS       set the read timeout to SECS.
  -w,  --wait=SECONDS            wait SECONDS between retrievals.
	   --waitretry=SECONDS       wait 1..SECONDS between retries of a retrieval.
	   --random-wait             wait from 0.5*WAIT...1.5*WAIT secs between retrievals.
	   --no-proxy                explicitly turn off proxy.
  -Q,  --quota=NUMBER            set retrieval quota to NUMBER.
	   --bind-address=ADDRESS    bind to ADDRESS (hostname or IP) on local host.
	   --limit-rate=RATE         limit download rate to RATE.
	   --no-dns-cache            disable caching DNS lookups.
	   --restrict-file-names=OS  restrict chars in file names to ones OS allows.
	   --ignore-case             ignore case when matching files/directories.
  -4,  --inet4-only              connect only to IPv4 addresses.
  -6,  --inet6-only              connect only to IPv6 addresses.
	   --prefer-family=FAMILY    connect first to addresses of specified family,
								 one of IPv6, IPv4, or none.
	   --user=USER               set both ftp and http user to USER.
	   --password=PASS           set both ftp and http password to PASS.
	   --ask-password            prompt for passwords.
	   --no-iri                  turn off IRI support.
	   --local-encoding=ENC      use ENC as the local encoding for IRIs.
	   --remote-encoding=ENC     use ENC as the default remote encoding.
	   --unlink                  remove file before clobber.

Directories:
  -nd, --no-directories           don't create directories.
  -x,  --force-directories        force creation of directories.
  -nH, --no-host-directories      don't create host directories.
	   --protocol-directories     use protocol name in directories.
  -P,  --directory-prefix=PREFIX  save files to PREFIX/...
	   --cut-dirs=NUMBER          ignore NUMBER remote directory components.

HTTP options:
	   --http-user=USER        set http user to USER.
	   --http-password=PASS    set http password to PASS.
	   --no-cache              disallow server-cached data.
	   --default-page=NAME     Change the default page name (normally
							   this is `index.html'.).
  -E,  --adjust-extension      save HTML/CSS documents with proper extensions.
	   --ignore-length         ignore `Content-Length' header field.
	   --header=STRING         insert STRING among the headers.
	   --max-redirect          maximum redirections allowed per page.
	   --proxy-user=USER       set USER as proxy username.
	   --proxy-password=PASS   set PASS as proxy password.
	   --referer=URL           include `Referer: URL' header in HTTP request.
	   --save-headers          save the HTTP headers to file.
  -U,  --user-agent=AGENT      identify as AGENT instead of Wget/VERSION.
	   --no-http-keep-alive    disable HTTP keep-alive (persistent connections).
	   --no-cookies            don't use cookies.
	   --load-cookies=FILE     load cookies from FILE before session.
	   --save-cookies=FILE     save cookies to FILE after session.
	   --keep-session-cookies  load and save session (non-permanent) cookies.
	   --post-data=STRING      use the POST method; send STRING as the data.
	   --post-file=FILE        use the POST method; send contents of FILE.
	   --content-disposition   honor the Content-Disposition header when
							   choosing local file names (EXPERIMENTAL).
	   --content-on-error      output the received content on server errors.
	   --auth-no-challenge     send Basic HTTP authentication information
							   without first waiting for the server's
							   challenge.

HTTPS (SSL/TLS) options:
	   --secure-protocol=PR     choose secure protocol, one of auto, SSLv2,
								SSLv3, and TLSv1.
	   --no-check-certificate   don't validate the server's certificate.
	   --certificate=FILE       client certificate file.
	   --certificate-type=TYPE  client certificate type, PEM or DER.
	   --private-key=FILE       private key file.
	   --private-key-type=TYPE  private key type, PEM or DER.
	   --ca-certificate=FILE    file with the bundle of CA's.
	   --ca-directory=DIR       directory where hash list of CA's is stored.
	   --random-file=FILE       file with random data for seeding the SSL PRNG.
	   --egd-file=FILE          file naming the EGD socket with random data.

FTP options:
	   --ftp-user=USER         set ftp user to USER.
	   --ftp-password=PASS     set ftp password to PASS.
	   --no-remove-listing     don't remove `.listing' files.
	   --no-glob               turn off FTP file name globbing.
	   --no-passive-ftp        disable the "passive" transfer mode.
	   --preserve-permissions  preserve remote file permissions.
	   --retr-symlinks         when recursing, get linked-to files (not dir).

WARC options:
	   --warc-file=FILENAME      save request/response data to a .warc.gz file.
	   --warc-header=STRING      insert STRING into the warcinfo record.
	   --warc-max-size=NUMBER    set maximum size of WARC files to NUMBER.
	   --warc-cdx                write CDX index files.
	   --warc-dedup=FILENAME     do not store records listed in this CDX file.
	   --no-warc-compression     do not compress WARC files with GZIP.
	   --no-warc-digests         do not calculate SHA1 digests.
	   --no-warc-keep-log        do not store the log file in a WARC record.
	   --warc-tempdir=DIRECTORY  location for temporary files created by the
								 WARC writer.

Recursive download:
  -r,  --recursive          specify recursive download.
  -l,  --level=NUMBER       maximum recursion depth (inf or 0 for infinite).
	   --delete-after       delete files locally after downloading them.
  -k,  --convert-links      make links in downloaded HTML or CSS point to
							local files.
  -K,  --backup-converted   before converting file X, back up as X.orig.
  -m,  --mirror             shortcut for -N -r -l inf --no-remove-listing.
  -p,  --page-requisites    get all images, etc. needed to display HTML page.
	   --strict-comments    turn on strict (SGML) handling of HTML comments.

Recursive accept/reject:
  -A,  --accept=LIST               comma-separated list of accepted extensions.
  -R,  --reject=LIST               comma-separated list of rejected extensions.
	   --accept-regex=REGEX        regex matching accepted URLs.
	   --reject-regex=REGEX        regex matching rejected URLs.
	   --regex-type=TYPE           regex type (posix).
  -D,  --domains=LIST              comma-separated list of accepted domains.
	   --exclude-domains=LIST      comma-separated list of rejected domains.
	   --follow-ftp                follow FTP links from HTML documents.
	   --follow-tags=LIST          comma-separated list of followed HTML tags.
	   --ignore-tags=LIST          comma-separated list of ignored HTML tags.
  -H,  --span-hosts                go to foreign hosts when recursive.
  -L,  --relative                  follow relative links only.
  -I,  --include-directories=LIST  list of allowed directories.
  --trust-server-names             use the name specified by the redirection
								   url last component.
  -X,  --exclude-directories=LIST  list of excluded directories.
  -np, --no-parent                 don't ascend to the parent directory.