1OPENSSL-REHASH(1ossl)               OpenSSL              OPENSSL-REHASH(1ossl)
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NAME

6       openssl-rehash, c_rehash - Create symbolic links to files named by the
7       hash values
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SYNOPSIS

10       openssl rehash [-h] [-help] [-old] [-compat] [-n] [-v] [-provider name]
11       [-provider-path path] [-propquery propq] [directory] ...
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13       c_rehash [-h] [-help] [-old] [-n] [-v] [-provider name] [-provider-path
14       path] [-propquery propq] [directory] ...
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DESCRIPTION

17       This command is generally equivalent to the external script c_rehash,
18       except for minor differences noted below.
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20       openssl rehash scans directories and calculates a hash value of each
21       .pem, .crt, .cer, or .crl file in the specified directory list and
22       creates symbolic links for each file, where the name of the link is the
23       hash value.  (If the platform does not support symbolic links, a copy
24       is made.)  This command is useful as many programs that use OpenSSL
25       require directories to be set up like this in order to find
26       certificates.
27
28       If any directories are named on the command line, then those are
29       processed in turn. If not, then the SSL_CERT_DIR environment variable
30       is consulted; this should be a colon-separated list of directories,
31       like the Unix PATH variable.  If that is not set then the default
32       directory (installation-specific but often /usr/local/ssl/certs) is
33       processed.
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35       In order for a directory to be processed, the user must have write
36       permissions on that directory, otherwise an error will be generated.
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38       The links created are of the form HHHHHHHH.D, where each H is a
39       hexadecimal character and D is a single decimal digit.  When a
40       directory is processed, all links in it that have a name in that syntax
41       are first removed, even if they are being used for some other purpose.
42       To skip the removal step, use the -n flag.  Hashes for CRL's look
43       similar except the letter r appears after the period, like this:
44       HHHHHHHH.rD.
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46       Multiple objects may have the same hash; they will be indicated by
47       incrementing the D value. Duplicates are found by comparing the full
48       SHA-1 fingerprint. A warning will be displayed if a duplicate is found.
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50       A warning will also be displayed if there are files that cannot be
51       parsed as either a certificate or a CRL or if more than one such object
52       appears in the file.
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54   Script Configuration
55       The c_rehash script uses the openssl program to compute the hashes and
56       fingerprints. If not found in the user's PATH, then set the OPENSSL
57       environment variable to the full pathname.  Any program can be used, it
58       will be invoked as follows for either a certificate or CRL:
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60         $OPENSSL x509 -hash -fingerprint -noout -in FILENAME
61         $OPENSSL crl -hash -fingerprint -noout -in FILENAME
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63       where FILENAME is the filename. It must output the hash of the file on
64       the first line, and the fingerprint on the second, optionally prefixed
65       with some text and an equals sign.
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OPTIONS

68       -help -h
69           Display a brief usage message.
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71       -old
72           Use old-style hashing (MD5, as opposed to SHA-1) for generating
73           links to be used for releases before 1.0.0.  Note that current
74           versions will not use the old style.
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76       -n  Do not remove existing links.  This is needed when keeping new and
77           old-style links in the same directory.
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79       -compat
80           Generate links for both old-style (MD5) and new-style (SHA1)
81           hashing.  This allows releases before 1.0.0 to use these links
82           along-side newer releases.
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84       -v  Print messages about old links removed and new links created.  By
85           default, this command only lists each directory as it is processed.
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87       -provider name
88       -provider-path path
89       -propquery propq
90           See "Provider Options" in openssl(1), provider(7), and property(7).
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ENVIRONMENT

93       OPENSSL
94           The path to an executable to use to generate hashes and
95           fingerprints (see above).
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97       SSL_CERT_DIR
98           Colon separated list of directories to operate on.  Ignored if
99           directories are listed on the command line.
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SEE ALSO

102       openssl(1), openssl-crl(1), openssl-x509(1)
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105       Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
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107       Licensed under the Apache License 2.0 (the "License").  You may not use
108       this file except in compliance with the License.  You can obtain a copy
109       in the file LICENSE in the source distribution or at
110       <https://www.openssl.org/source/license.html>.
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1143.1.1                             2023-08-31             OPENSSL-REHASH(1ossl)
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