Curl command reference with options sorted by category for easier usage than that man page.

curl reference

==========================================      
             CURL COMMAND
==========================================

Format       curl [options] [URL...]

Quick Ref: 

   curl -X POST http://example.com/   <= Method option and URL (Options come before or after URL)
        -H "Authorization: <data>"    <= Add HTTP Header (like Authorization)
                                         -H "Authorization: Token token=a47a8e54b11c4de5a4a351734c80a14a"
        -A "user-agent-string"        <= Specify an Agent
        -b "name=data"                <= Send cookies
        -u "user:password"            <= Basic HTTP Auth (or "<apikey>:")
        -H "Range: page=1"            <= Range header for pagination
        -H "Accept: application/vnd.mycompany.api.v3+json"
                                      <= Specify API version and JSON as Content-Type
                                      
        -d "name=value"               <= Multiple POST parameters
        --data-urlencode "name=value" <= SAFER: URL-Encodes the POST parameter (with special characters)
        -F "name=@/path/file"         <= Multiple File Uploads
        -F "webpage=@index.html;filename=index.html;type=text/html"
        -I                            <= Make HEAD request only
        
        -i                            <= Print response headers
        -v                            <= Verbose, see request and response
        -sS                           <= Do not print status bar (in scripts)
        

OPERATIONS
             -# --progress-bar
             --environment
             -f --fail (fail silently)
             -g --globoff
             -K --config <config file>
             --libcurl <file>
             -n --netrc (.netrc password file)
             --netrc-file <alt-filename>
             --netrc-optional
             --proto <protocols>
             --proto-redir <protocols>
             -q (skip .curlrc)
             --retry <num>
             --retry-delay <seconds>
             --retry-max-time <seconds>
             -s --silent
             -S --show-error
             -y --speed-time <time>
             -Y --speed-limit <speed>
             -h --help
             -M --manual
             -V --version
             .
NETWORK
             -4 --ipv4
             -6 --ipv6
             ---connect-timeout <seconds>
             --interface <name>
             --keepalive-time <seconds>
             --limit-rate <speed>
             --local-port <num>[-num]
             --no-keepalive
             --noproxy <list>
             -p --proxytunnel
             --proxy1.0 <proxyhost[:port]>
             --resolve <host:port:address>
             --socks4 <host:port>
             --socks4a <host:port>
             --socks5-hostname <host:port>
             --socks5 <host:port>
             --socks5-gssapi-service <name>
             --socks5-gssapi-nec
             -t --telnet-option <OPT=val>
             --tcp-nodelay
             -x --proxy <protocol:://[user@pw:]host:port>
             .
OUTPUT
             -a --append
             -B --use-ascii
             -C --continue-at <offset>
             --create-dirs
             --crlf
             -D --dump-header <file>
             --max-filesize <bytes>
             -N --no-buffer
             -o --output <file>
             -O --remote-name (save with remote naming)
             -r --range <range> (byte range)
             -R --remote-file (set file to remote timestamp)
             --raw
             --remote-name-all
             --stderr <file>
             --trace <file>
             --trace-ascii <file>
             --trace-time
             -v --verbose
             -w --write-out <format>
             --xattr
             .
HTTP
             -0 --http1.0
             -3 --tlsv3
             --compressed
             --crlfile <file>
             --ignore-content-length
             -I --head (headers only)
             -O --remote-name
                -J --remote-header-name
             -L --location (follow redirect)
             --location-trusted (redirect with name/pw)
             --max-redirs <num>
             --negotiate
             --ntlm
             --url <URL>
             .
SSL
             -1 --tlsv1
             -2 --tlsv2
             --cyphers <list>
             -E --cert <certificate[:password]>
             --engine <name>
             --egd-file <file>
             --cert-type <type>
             --cacert <CA certificate>
             --capath <CA certificate directory>
             -k --insecure
             --key <private key file name>
             --key-type <DER|PEM|ENG>
             --no-sessionid
             --random-file <file>
             --ssl
             --ssl-reqd
             .
AUTHENTICATION
             --anyauth
             --basic
             --delegation <none|policy|always>
             --digest
             --proxy-anyauth
             --proxy-basic
             --proxy-digest
             --proxy-negotiate
             --proxy-ntlm
             --tlsauthtype <authtype>
             --tlsuser <user>
             --tlspassword
             -u --user <user:password>
             -U --proxy-user <user:password>
             .
HEADERS
             -A --user-agent <string>
             -b --cookie <name=data>
             -c --cookie-jar <file>
                -j --junk-session-cookies
             -e --referer <URL>
             -H --header <header>
             --tr-encoding (compressed transfers)
             .
REQUEST
             --post301
             --post302
             -T --upload-file <file>
             -X --request <command>
                PUT DELETE PATCH, WebDAV
             -z --time-cond <date expression>
  GET        .
             -G --get
             .
  POST DATA  .
             -d --data <data>
             --data-ascii <data>
             --data-binary <data>
             --data-urlencode <data>
                 content (no @, =)
                 =content (allows @, =)
                 name=content
                 @filename (filedata)
                 name@filename (name=filedata)
             .
  POST       .
             -F --form <name=content>
                 name=data
                 name=data;type=text/foo
                 name=@index.html;type=text/html
                 name=@filename;filename=postname
             --form-string <name=string> (literal)
             .
FTP            
             --disable-epsc
             --ftp-account [data]
             --ftp-alternative-to-user <command>
             --ftp-create-dirs
             --ftp-method [multicwd|nocwd|singlecwd]
             --ftp-pasv
             --ftp-skip-pasv-ip
             --ftp-pret
             --ftp-ssl-ccc
             --ftp-ssl-ccc-mode [active|passsive]
             --ftp-ssl-control
             --krv <level>
             -- --list-only
             -P --ftp-port <interface|ipaddress|hostname|->
             -Q --quote <command>
             --tftp-blksize <value>
             .
SCP/SFTP
             --hostpubmd4 <md5>
             --pass <phrase>
             .
SMTP
             --mail-from <address>
             --mailprcpt <address>
             .