使い方: chpasswd [オプション] オプション: -c, --crypt-method METHOD 暗号化の方法 (NONE DES MD5 SHA256 SHA512 のどれかひとつ) -e, --encrypted 与えたパスワードを暗号化する -h, --help このヘルプを表示して終了する -m, --md5 平文テキストのパスワードを MD5 アルゴリズムで暗号化する -R, --root CHROOT_DIR chroot するディレクトリ -s, --sha-rounds SHA* 暗号化アルゴリズムの SHA ラウンド回数
Usage: chpasswd [options] Options: -c, --crypt-method METHOD the crypt method (one of NONE DES MD5 SHA256 SHA512) -e, --encrypted supplied passwords are encrypted -h, --help display this help message and exit -m, --md5 encrypt the clear text password using the MD5 algorithm -R, --root CHROOT_DIR directory to chroot into -s, --sha-rounds number of SHA rounds for the SHA* crypt algorithms
CHPASSWD(8) CHPASSWD(8) 名前 chpasswd - パスワードファイルをバッチ処理で更新する 書式 chpasswd [-e] 説明 chpasswd コマンドは標準入力からユーザ名とパスワードの組が記されているフ ァイルを読み込み、その情報を用いて既存のユーザ群のパスワード情報を更 新 す る。 -e オプションがない場合は、パスワードは平文とみなされる。 -e オ プションがある場合は、パスワードは暗号化されているとみなされる。各行 の 書式は次の通り。 user_name:password 指 定したユーザは既に存在していなければならない。与えられたパスワードは 必要に応じて暗号化され、パスワードの有効期限がある場合はそれも更新さ れ る。 こ のコマンドは、同時に大量のアカウントを作成するような、大規模なシステ ム環境で用いるために作られた。 警告 入力ファイルに暗号化されていないパスワードが記されている場合は、適切 に 保護しておかなければならない。 関連項目 passwd(1), newusers(8), useradd(8) 著者 Julianne Frances Haugh (jockgrrl@ix.netcom.com) CHPASSWD(8)
CHPASSWD(8) System Management Commands CHPASSWD(8) NAME chpasswd - update passwords in batch mode SYNOPSIS chpasswd [options] DESCRIPTION The chpasswd command reads a list of user name and password pairs from standard input and uses this information to update a group of existing users. Each line is of the format: user_name:password By default the passwords must be supplied in clear-text, and are encrypted by chpasswd. Also the password age will be updated, if present. The default encryption algorithm can be defined for the system with the ENCRYPT_METHOD or MD5_CRYPT_ENAB variables of /etc/login.defs, and can be overwitten with the -e, -m, or -c options. chpasswd first updates all the passwords in memory, and then commits all the changes to disk if no errors occured for any user. This command is intended to be used in a large system environment where many accounts are created at a single time. OPTIONS The options which apply to the chpasswd command are: -c, --crypt-method METHOD Use the specified method to encrypt the passwords. The available methods are DES, MD5, NONE, and SHA256 or SHA512 if your libc support these methods. By default (if none of the -c, -m, or -e options are specified), the encryption method is defined by the ENCRYPT_METHOD or MD5_CRYPT_ENAB variables of /etc/login.defs. -e, --encrypted Supplied passwords are in encrypted form. -h, --help Display help message and exit. -m, --md5 Use MD5 encryption instead of DES when the supplied passwords are not encrypted. -R, --root CHROOT_DIR Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory. -s, --sha-rounds ROUNDS Use the specified number of rounds to encrypt the passwords. The value 0 means that the system will choose the default number of rounds for the crypt method (5000). A minimal value of 1000 and a maximal value of 999,999,999 will be enforced. You can only use this option with the SHA256 or SHA512 crypt method. By default, the number of rounds is defined by the SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in /etc/login.defs. CAVEATS Remember to set permissions or umask to prevent readability of unencrypted files by other users. CONFIGURATION The following configuration variables in /etc/login.defs change the behavior of this tool: ENCRYPT_METHOD (string) This defines the system default encryption algorithm for encrypting passwords (if no algorithm are specified on the command line). It can take one of these values: DES (default), MD5, SHA256, SHA512. Note: this parameter overrides the MD5_CRYPT_ENAB variable. MD5_CRYPT_ENAB (boolean) Indicate if passwords must be encrypted using the MD5-based algorithm. If set to yes, new passwords will be encrypted using the MD5-based algorithm compatible with the one used by recent releases of FreeBSD. It supports passwords of unlimited length and longer salt strings. Set to no if you need to copy encrypted passwords to other systems which don´t understand the new algorithm. Default is no. This variable is superseded by the ENCRYPT_METHOD variable or by any command line option used to configure the encryption algorithm. This variable is deprecated. You should use ENCRYPT_METHOD. SHA_CRYPT_MIN_ROUNDS (number), SHA_CRYPT_MAX_ROUNDS (number) When ENCRYPT_METHOD is set to SHA256 or SHA512, this defines the number of SHA rounds used by the encryption algorithm by default (when the number of rounds is not specified on the command line). With a lot of rounds, it is more difficult to brute forcing the password. But note also that more CPU resources will be needed to authenticate users. If not specified, the libc will choose the default number of rounds (5000). The values must be inside the 1000-999,999,999 range. If only one of the SHA_CRYPT_MIN_ROUNDS or SHA_CRYPT_MAX_ROUNDS values is set, then this value will be used. If SHA_CRYPT_MIN_ROUNDS > SHA_CRYPT_MAX_ROUNDS, the highest value will be used. FILES /etc/passwd User account information. /etc/shadow Secure user account information. /etc/login.defs Shadow password suite configuration. SEE ALSO passwd(1), newusers(8), login.defs(5), useradd(8). shadow-utils 4.1.5.1 05/10/2016 CHPASSWD(8)
Copyright(C) linux-cmd.com All Rights Reserved. Author Takayuki Yukawa