openssl x509 --help

unknown option --help
usage: x509 [-C] [-addreject arg] [-addtrust arg] [-alias] [-CA file]
    [-CAcreateserial] [-CAform der | pem] [-CAkey file]
    [-CAkeyform der | pem] [-CAserial file] [-certopt option]
    [-checkend arg] [-clrext] [-clrreject] [-clrtrust] [-dates]
    [-days arg] [-email] [-enddate] [-extensions section]
    [-extfile file] [-fingerprint] [-hash] [-in file]
    [-inform der | net | pem] [-issuer] [-issuer_hash]
    [-issuer_hash_old] [-keyform der | pem] [-md5 | -sha1]
    [-modulus] [-nameopt option] [-next_serial] [-noout]
    [-ocsp_uri] [-ocspid] [-out file]
    [-outform der | net | pem] [-passin arg] [-pubkey]
    [-purpose] [-req] [-serial] [-set_serial n] [-setalias arg]
    [-signkey file] [-sigopt nm:v] [-startdate] [-subject]
    [-subject_hash] [-subject_hash_old] [-text] [-trustout]
    [-x509toreq]

 -C                 Convert the certificate into C code
 -addreject arg     Reject certificate for a given purpose
 -addtrust arg      Trust certificate for a given purpose
 -alias             Output certificate alias
 -CA file           CA certificate in PEM format unless -CAform is specified
 -CAcreateserial    Create serial number file if it does not exist
 -CAform fmt        CA format - default PEM
 -CAkey file        CA key in PEM format unless -CAkeyform is specified
                    if omitted, the key is assumed to be in the CA file
 -CAkeyform fmt     CA key format - default PEM
 -CAserial file     Serial file
 -certopt option    Various certificate text options
 -checkend arg      Check whether the cert expires in the next arg seconds
                    exit 1 if so, 0 if not
 -clrext            Clear all extensions
 -clrreject         Clear all rejected purposes
 -clrtrust          Clear all trusted purposes
 -dates             Both Before and After dates
 -days arg          How long till expiry of a signed certificate - def 30 days
 -email             Print email address(es)
 -enddate           Print notAfter field
 -extensions section
                    Section from config file with X509V3 extensions to add
 -extfile file      Configuration file with X509V3 extensions to add
 -fingerprint       Print the certificate fingerprint
 -hash              Synonym for -subject_hash
 -in file           Input file - default stdin
 -inform fmt        Input format - default PEM (one of DER, NET or PEM)
 -issuer            Print issuer name
 -issuer_hash       Print issuer hash value
 -issuer_hash_old   Print old-style (MD5) issuer hash value
 -keyform fmt       Private key format - default PEM
 -modulus           Print the RSA key modulus
 -nameopt option    Various certificate name options
 -next_serial       Print the next serial number
 -noout             No certificate output
 -ocsp_uri          Print OCSP Responder URL(s)
 -ocspid            Print OCSP hash values for the subject name and public key
 -out file          Output file - default stdout
 -outform fmt       Output format - default PEM (one of DER, NET or PEM)
 -passin src        Private key password source
 -pubkey            Output the public key
 -purpose           Print out certificate purposes
 -req               Input is a certificate request, sign and output
 -serial            Print serial number value
 -set_serial n      Serial number to use
 -setalias arg      Set certificate alias
 -signkey file      Self sign cert with arg
 -sigopt nm:v       Various signature algorithm options
 -startdate         Print notBefore field
 -subject           Print subject name
 -subject_hash      Print subject hash value
 -subject_hash_old  Print old-style (MD5) subject hash value
 -text              Print the certificate in text form
 -trustout          Output a trusted certificate
 -x509toreq         Output a certification request object

See also

• openssl x509[ -inform | -text | -dates | -subject | --help]