LOGIN.DEFS(5) (NAME) login.defs - shadow (DESCRIPTION) /etc/login.defs shadow . . . . (whitespace) . . <<#>> . : . . yes no . no . ( ) ( 0 ) ( 0x ) . . : CHFN_RESTRICT () gecos /etc/passwd chfn . f r w h (Full name) (Room number) (Work phone) (Home phone) . yes rwh no frwh . ( ) . chfn SUID . CREATE_HOME () . (override) . DEFAULT_HOME () cd (login) . no . yes (/) . ENCRYPT_METHOD () ( ) . : DES () MD5 SHA256 SHA512 YESCRYPT. MD5 DES crypt(5) . : MD5_CRYPT_ENAB (override) . : . PAM PAM . PAM . ENV_PATH () PATH . ( /bin:/usr/bin) PATH= . PATH=/bin:/usr/bin . ENV_SUPATH () PATH ( ) . ( /sbin:/bin:/usr/sbin:/usr/bin) PATH= . PATH=/sbin:/bin:/usr/sbin:/usr/bin . ERASECHAR () ERASE (010 = backspace 0177 = DEL). <<0>> <<0x>> . FAIL_DELAY () . FAKE_SHELL () login /etc/passwd . GID_MAX () GID_MIN () (GID) useradd groupadd newusers. GID_MIN ( GID_MAX) 1000 ( 60000) . HOME_MODE () (mode) . UMASK . useradd newusers . HUSHLOGIN_FILE () . (hushed mode) . . KILLCHAR () KILL (025 = CTRL/U). <<0>> <<0x>> . LASTLOG_UID_MAX () (UID) lastlog . lastlog (sparse) . LASTLOG_UID_MAX lastlog . LOG_OK_LOGINS () () . LOG_UNKFAIL_ENAB () . : . LOGIN_RETRIES () . PAM pam_unix . PAM_MAXTRIES (fallback) . LOGIN_TIMEOUT () . MAIL_DIR () (mail spool). . . CREATE_MAIL_SPOOL /etc/default/useradd . MAIL_FILE () . MAIL_DIR MAIL_FILE useradd usermod userdel . MAX_MEMBERS_PER_GROUP () . () /etc/group ( GID). 0 . ( split group) . NIS . 25 . : ( Shadow). . MD5_CRYPT_ENAB () MD5 . yes MD5 FreeBSD . (salt) . no . no . ENCRYPT_METHOD . (deprecated) ENCRYPT_METHOD . : . PAM PAM . PAM . NONEXISTENT () /etc/passwd . pwck . PASS_MAX_DAYS () . . 1- ( ). PASS_MIN_DAYS () . . 0 ( ). PASS_WARN_AGE () . 1- . . PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE . . SHA_CRYPT_MIN_ROUNDS () SHA_CRYPT_MAX_ROUNDS () ENCRYPT_METHOD SHA256 SHA512 SHA ( ) . (brute force) . (CPU) . libc (5000) . 1000 999,999,999 . SHA_CRYPT_MIN_ROUNDS SHA_CRYPT_MAX_ROUNDS . SHA_CRYPT_MIN_ROUNDS > SHA_CRYPT_MAX_ROUNDS . : . PAM PAM . PAM . SULOG_FILE () su . SU_NAME () <> . <> <> <<-su>> . <> <<-sh>>. SUB_GID_MIN () SUB_GID_MAX () SUB_GID_COUNT () /etc/subuid useradd newusers ( ) SUB_GID_COUNT SUB_GID_MIN SUB_GID_MAX . SUB_GID_MIN SUB_GID_MAX SUB_GID_COUNT . SUB_UID_MIN () SUB_UID_MAX () SUB_UID_COUNT () /etc/subuid useradd newusers ( ) SUB_UID_COUNT SUB_UID_MIN SUB_UID_MAX . SUB_UID_MIN SUB_UID_MAX SUB_UID_COUNT . SYS_GID_MAX () SYS_GID_MIN () useradd groupadd newusers. SYS_GID_MIN ( SYS_GID_MAX) 101 ( GID_MIN-1) . SYS_UID_MAX () SYS_UID_MIN () useradd newusers. SYS_UID_MIN ( SYS_UID_MAX) 101 ( UID_MIN-1) . SYSLOG_SG_ENAB () <> sg. SYSLOG_SU_ENAB () <> su - sulog. TTYGROUP () TTYPERM () : tty TTYGROUP TTYPERM . TTYGROUP . TTYGROUP . TTYPERM 0600 . write <> TTYGROUP TTYPERM 0620 . TTYGROUP TTYPERM 622 600 . TTYTYPE_FILE () tty TERM . <> . UID_MAX () UID_MIN () useradd newusers. UID_MIN ( UID_MAX) 1000 ( 60000) . UMASK () . 022 . useradd newusers HOME_MODE . pam_umask umask . USERDEL_CMD () . at/cron/print ( ) . . cron at : #! /bin/sh # . if [ $# != 1 ]; then echo "Usage: $0 username" exit 1 fi # cron. crontab -r -u $1 # at. # UID # . AT_SPOOL_DIR=/var/spool/cron/atjobs find $AT_SPOOL_DIR -name "[^.]*" -type f -user $1 -delete \; # . lprm $1 # . exit 0 USERGROUPS_ENAB () yes userdel useradd . YESCRYPT_COST_FACTOR () ENCRYPT_METHOD YESCRYPT (cost factor) ( ) . (brute force) (CPU) . . : . PAM PAM . PAM . (CROSS REFERENCES) shadow . chfn CHFN_RESTRICT chgpasswd ENCRYPT_METHOD MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS YESCRYPT_COST_FACTOR chpasswd SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS YESCRYPT_COST_FACTOR gpasswd ENCRYPT_METHOD MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS YESCRYPT_COST_FACTOR groupadd GID_MAX GID_MIN MAX_MEMBERS_PER_GROUP SYS_GID_MAX SYS_GID_MIN groupdel MAX_MEMBERS_PER_GROUP groupmems MAX_MEMBERS_PER_GROUP groupmod MAX_MEMBERS_PER_GROUP grpck MAX_MEMBERS_PER_GROUP grpconv MAX_MEMBERS_PER_GROUP grpunconv MAX_MEMBERS_PER_GROUP lastlog LASTLOG_UID_MAX login CONSOLE_GROUPS DEFAULT_HOME ERASECHAR FAIL_DELAY FAKE_SHELL HUSHLOGIN_FILE KILLCHAR LOGIN_RETRIES LOGIN_TIMEOUT LOG_OK_LOGINS LOG_UNKFAIL_ENAB TTYGROUP TTYPERM TTYTYPE_FILE USERGROUPS_ENAB newgrp / sg SYSLOG_SG_ENAB newusers ENCRYPT_METHOD GID_MAX GID_MIN MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB HOME_MODE PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS SUB_GID_COUNT SUB_GID_MAX SUB_GID_MIN SUB_UID_COUNT SUB_UID_MAX SUB_UID_MIN SYS_GID_MAX SYS_GID_MIN SYS_UID_MAX SYS_UID_MIN UID_MAX UID_MIN UMASK YESCRYPT_COST_FACTOR pwck PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE pwconv PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE su CONSOLE_GROUPS DEFAULT_HOME ENV_PATH ENV_SUPATH SULOG_FILE SU_NAME SYSLOG_SU_ENAB useradd CREATE_HOME GID_MAX GID_MIN HOME_MODE LASTLOG_UID_MAX MAIL_DIR MAX_MEMBERS_PER_GROUP PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE SUB_GID_COUNT SUB_GID_MAX SUB_GID_MIN SUB_UID_COUNT SUB_UID_MAX SUB_UID_MIN SYS_GID_MAX SYS_GID_MIN SYS_UID_MAX SYS_UID_MIN UID_MAX UID_MIN UMASK userdel MAIL_DIR MAIL_FILE MAX_MEMBERS_PER_GROUP USERDEL_CMD USERGROUPS_ENAB usermod LASTLOG_UID_MAX MAIL_DIR MAIL_FILE MAX_MEMBERS_PER_GROUP (BUGS) shadow PAM . /etc/login.defs passwd(1) login(1) su(1) . PAM . (SEE ALSO) login(1) passwd(1) su(1) passwd(5) shadow(5) pam(8). shadow-utils 4.17.4 04/19/2025 LOGIN.DEFS(5)