wget: Option Syntax
2.2 Option Syntax
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Since Wget uses GNU getopt to process command-line arguments, every
option has a long form along with the short one. Long options are more
convenient to remember, but take time to type. You may freely mix
different option styles, or specify options after the command-line
arguments. Thus you may write:
wget -r --tries=10 http://fly.srk.fer.hr/ -o log
The space between the option accepting an argument and the argument
may be omitted. Instead of ‘-o log’ you can write ‘-olog’.
You may put several options that do not require arguments together,
like:
wget -drc URL
This is completely equivalent to:
wget -d -r -c URL
Since the options can be specified after the arguments, you may
terminate them with ‘--’. So the following will try to download URL
‘-x’, reporting failure to ‘log’:
wget -o log -- -x
The options that accept comma-separated lists all respect the
convention that specifying an empty list clears its value. This can be
useful to clear the ‘.wgetrc’ settings. For instance, if your ‘.wgetrc’
sets ‘exclude_directories’ to ‘/cgi-bin’, the following example will
first reset it, and then set it to exclude ‘/~nobody’ and ‘/~somebody’.
You can also clear the lists in ‘.wgetrc’ (⇒Wgetrc Syntax).
wget -X "" -X /~nobody,/~somebody
Most options that do not accept arguments are “boolean” options, so
named because their state can be captured with a yes-or-no (“boolean”)
variable. For example, ‘--follow-ftp’ tells Wget to follow FTP links
from HTML files and, on the other hand, ‘--no-glob’ tells it not to
perform file globbing on FTP URLs. A boolean option is either
“affirmative” or “negative” (beginning with ‘--no’). All such options
share several properties.
Unless stated otherwise, it is assumed that the default behavior is
the opposite of what the option accomplishes. For example, the
documented existence of ‘--follow-ftp’ assumes that the default is to
_not_ follow FTP links from HTML pages.
Affirmative options can be negated by prepending the ‘--no-’ to the
option name; negative options can be negated by omitting the ‘--no-’
prefix. This might seem superfluous—if the default for an affirmative
option is to not do something, then why provide a way to explicitly turn
it off? But the startup file may in fact change the default. For
instance, using ‘follow_ftp = on’ in ‘.wgetrc’ makes Wget _follow_ FTP
links by default, and using ‘--no-follow-ftp’ is the only way to restore
the factory default from the command line.