transfer a URL
(HTTP) Fail silently (no output at all) on server errors. This is mostly done to better enable
scripts etc to better deal with failed attempts. In normal cases when a HTTP server fails to
deliver a document, it returns an HTML document stating so (which often also describes why and
more). This flag will prevent curl from outputting that and return error 22.
This method is not fail-safe and there are occasions where non-successful response codes will slip
through, especially when authentication is involved (response codes 401 and 407).
Silent or quiet mode. Don't show progress meter or error messages. Makes Curl mute.
When used with -s it makes curl show an error message if it fails.
(HTTP/HTTPS) If the server reports that the requested page has moved to a different location
(indicated with a Location: header and a 3XX response code), this option will make curl redo the
request on the new place. If used together with -i, --include or -I, --head, headers from all
requested pages will be shown. When authentication is used, curl only sends its credentials to the
initial host. If a redirect takes curl to a different host, it won't be able to intercept the
user+password. See also --location-trusted on how to change this. You can limit the amount of
redirects to follow by using the --max-redirs option.
When curl follows a redirect and the request is not a plain GET (for example POST or PUT), it will
do the following request with a GET if the HTTP response was 301, 302, or 303. If the response
code was any other 3xx code, curl will re-send the following request using the same unmodified
A pipeline is a sequence of one or more commands separated by one of the control operators | or |&. The
format for a pipeline is:
[time [-p]] [ ! ] command [ [|⎪|&] command2 ... ]
The standard output of command is connected via a pipe to the standard input of command2. This
connection is performed before any redirections specified by the command (see REDIRECTION below). If |&
is used, the standard error of command is connected to command2's standard input through the pipe; it is
shorthand for 2>&1 |. This implicit redirection of the standard error is performed after any
redirections specified by the command.
The return status of a pipeline is the exit status of the last command, unless the pipefail option is
enabled. If pipefail is enabled, the pipeline's return status is the value of the last (rightmost)
command to exit with a non-zero status, or zero if all commands exit successfully. If the reserved word
! precedes a pipeline, the exit status of that pipeline is the logical negation of the exit status as
described above. The shell waits for all commands in the pipeline to terminate before returning a value.
If the time reserved word precedes a pipeline, the elapsed as well as user and system time consumed by
its execution are reported when the pipeline terminates. The -p option changes the output format to that
specified by POSIX. When the shell is in posix mode, it does not recognize time as a reserved word if
the next token begins with a `-'. The TIMEFORMAT variable may be set to a format string that specifies
how the timing information should be displayed; see the description of TIMEFORMAT under Shell Variables
When the shell is in posix mode, time may be followed by a newline. In this case, the shell displays the
total user and system time consumed by the shell and its children. The TIMEFORMAT variable may be used
to specify the format of the time information.
Each command in a pipeline is executed as a separate process (i.e., in a subshell).
stream editor for filtering and transforming text
-n, --quiet, --silent
suppress automatic printing of pattern space
If no -e, --expression, -f, or --file option is given, then the first non-option argument is taken as the
sed script to interpret. All remaining arguments are names of input files; if no input files are
specified, then the standard input is read.
pattern-directed scanning and processing language