查看定时任务

看 /var/log/cron.log这个文件就可以

tail -f /var/log/cron

查看状态

service crond status
service crond start
service crond stop
service crond restart
service crond reload

查看定时任务列表

crontab -l

删除定时任务

crontab -r

crontab文件的一些例子：

30 21 * /usr/local/etc/rc.d/lighttpd restart

上面的例子表示每晚的21:30重启apache。

45 4 1,10,22 /usr/local/etc/rc.d/lighttpd restart

上面的例子表示每月1、10、22日的4 : 45重启apache。

定时任务链接

mysqldump备份不输入密码直接备份

1、在你的用户根目录下面创建一个.my.cnf 文件添加以下内容 [client] user=username---- 我的是root password=password----我的是1qazxsw2 2、添加完后修改他的权限防止其他用户使用 chmod 600 .my.cnf 3、下面就可以不输入密码直接使用了。 mysqldump -uroot -S /var/lib/mysql/mysql.sock --databases mysql |gzip -9>/soft/msyql.gz [root@mysql ~]# mysqldump -uroot -S /var/lib/mysql/mysql.sock --databases mysql |gzip -9>mysql.gz [root@mysql ~]# ls anaconda-ks.cfg install.log install.log.syslog mysql.gz 这样就可以不使用密码直接备份 这种情形适用于你制定定时备份任务 假如你计划晚上12点备份就可以通过crontab 来备份你的数据库 0 0 * mysqldump -u root -S /var/lib/mysql/mysql.sock --databases mysql |gzip -9>mysql.gz

[参考文档]（https://easyengine.io/tutorials/mysql/mycnf-preference/）

备份数据库脚本

#!/usr/bin/env bash

# Author:   Zhang Huangbin ([email protected])
# Date:     16/09/2007
# Purpose:  Backup specified mysql databases with command 'mysqldump'.
# License:  This shell script is part of iRedMail project, released under
#           GPL v2.

###########################
# REQUIREMENTS
###########################
#
#   * Required commands:
#       + mysqldump
#       + du
#       + bzip2     # If bzip2 is not available, change 'CMD_COMPRESS'
#                   # to use 'gzip'.
#

###########################
# USAGE
###########################
#
#   * It stores all backup copies in directory '/var/vmail/backup' by default,
#     You can change it in variable $BACKUP_ROOTDIR below.
#
#   * Set correct values for below variables:
#
#       BACKUP_ROOTDIR
#       MYSQL_ROOT_USER
#       DATABASES
#       DB_CHARACTER_SET
#
#   * Add crontab job for root user (or whatever user you want):
#
#       # crontab -e -u root
#       1   4   *   *   *   bash /path/to/backup_mysql.sh
#
#   * Make sure 'crond' service is running, and will start automatically when
#     system startup:
#
#       # ---- On RHEL/CentOS ----
#       # chkconfig --level 345 crond on
#       # /etc/init.d/crond status
#
#       # ---- On Debian/Ubuntu ----
#       # update-rc.d cron defaults
#       # /etc/init.d/cron status
#

#########################################################
# Modify below variables to fit your need ----
#########################################################
# Keep backup for how many days. Default is 90 days.
KEEP_DAYS='90'

# Where to store backup copies.
export BACKUP_ROOTDIR="/var/vmail/backup"

# MySQL username. Root user is required to dump all databases.
export MYSQL_ROOT_USER='root'

# ~/.my.cnf
export MYSQL_DOT_MY_CNF='/root/.my.cnf'

# Databases we should backup.
# Multiple databases MUST be seperated by SPACE.
export DATABASES='mysql vmail roundcubemail amavisd iredadmin sogo iredapd'

# Database character set for ALL databases.
# Note: Currently, it doesn't support to specify character set for each databases.
export DB_CHARACTER_SET="utf8"

#########################################################
# You do *NOT* need to modify below lines.
#########################################################
export PATH='/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/sbin'

# Commands.
export CMD_DATE='/bin/date'
export CMD_DU='du -sh'
export CMD_COMPRESS='bzip2 -9'
export COMPRESS_SUFFIX='bz2'
export CMD_MYSQL="mysql --defaults-file=${MYSQL_DOT_MY_CNF} -u${MYSQL_ROOT_USER}"
export CMD_MYSQLDUMP="mysqldump --defaults-file=${MYSQL_DOT_MY_CNF} -u${MYSQL_ROOT_USER} --events --ignore-table=mysql.event --default-character-set=${DB_CHARACTER_SET} --skip-comments"

# Date.
export YEAR="$(${CMD_DATE} +%Y)"
export MONTH="$(${CMD_DATE} +%m)"
export DAY="$(${CMD_DATE} +%d)"
export TIME="$(${CMD_DATE} +%H-%M-%S)"
export TIMESTAMP="${YEAR}-${MONTH}-${DAY}-${TIME}"

# Pre-defined backup status
export BACKUP_SUCCESS='YES'

# Define, check, create directories.
export BACKUP_DIR="${BACKUP_ROOTDIR}/mysql/${YEAR}/${MONTH}/${DAY}"

# Find the old backup which should be removed.
export REMOVE_OLD_BACKUP='NO'
if which python &>/dev/null; then
    export REMOVE_OLD_BACKUP='YES'
    py_cmd="import time; import datetime; t=time.localtime(); print datetime.date(t.tm_year, t.tm_mon, t.tm_mday) - datetime.timedelta(days=${KEEP_DAYS})"
    shift_date=$(python -c "${py_cmd}")
    shift_year="$(echo ${shift_date} | awk -F'-' '{print $1}')"
    shift_month="$(echo ${shift_date} | awk -F'-' '{print $2}')"
    shift_day="$(echo ${shift_date} | awk -F'-' '{print $3}')"
    export REMOVED_BACKUP_DIR="${BACKUP_ROOTDIR}/mysql/${shift_year}/${shift_month}/${shift_day}"
fi

# Log file
export LOGFILE="${BACKUP_DIR}/${TIMESTAMP}.log"

# Verify MySQL connection.
${CMD_MYSQL} -e "show databases" &>/dev/null
if [ X"$?" != X"0" ]; then
    echo "[ERROR] MySQL username or password is incorrect in file ${0}." 1>&2
    echo "Please fix them first." 1>&2

    exit 255
fi

# Check and create directories.
[ ! -d ${BACKUP_DIR} ] && mkdir -p ${BACKUP_DIR} 2>/dev/null
chown root ${BACKUP_DIR}
chmod 0700 ${BACKUP_DIR}

# Initialize log file.
echo "* Starting backup: ${TIMESTAMP}." >${LOGFILE}
echo "* Backup directory: ${BACKUP_DIR}." >>${LOGFILE}

# Backup.
echo "* Backing up databases: ${DATABASES}." >> ${LOGFILE}
for db in ${DATABASES}; do
    #backup_db ${db} >>${LOGFILE}

    #if [ X"$?" == X"0" ]; then
    #    echo "  - ${db} [DONE]" >> ${LOGFILE}
    #else
    #    [ X"${BACKUP_SUCCESS}" == X'YES' ] && export BACKUP_SUCCESS='NO'
    #fi
    output_sql="${BACKUP_DIR}/${db}-${TIMESTAMP}.sql"

    # Check database existence
    ${CMD_MYSQL} -e "USE ${db}" &>/dev/null

    if [ X"$?" == X'0' ]; then
        # Dump
        ${CMD_MYSQLDUMP} ${db} > ${output_sql}

        if [ X"$?" == X'0' ]; then
            # Get original SQL file size
            original_size="$(${CMD_DU} ${output_sql} | awk '{print $1}')"

            # Compress
            ${CMD_COMPRESS} ${output_sql} >>${LOGFILE}

            if [ X"$?" == X'0' ]; then
                rm -f ${output_sql} >> ${LOGFILE}
            fi

            # Get compressed file size
            compressed_file_name="${output_sql}.${COMPRESS_SUFFIX}"
            compressed_size="$(${CMD_DU} ${compressed_file_name} | awk '{print $1}')"

            sql_log_msg="INSERT INTO log (event, loglevel, msg, admin, ip, timestamp) VALUES ('backup', 'info', 'Database: ${db}, size: ${compressed_size} (original: ${original_size})', 'cron_backup_sql', '127.0.0.1', UTC_TIMESTAMP());"
        else
            # backup failed
            export BACKUP_SUCCESS='NO'
            sql_log_msg="INSERT INTO log (event, loglevel, msg, admin, ip, timestamp) VALUES ('backup', 'info', 'Database backup failed: ${db}. Log: $(cat ${LOGFILE})', 'cron_backup_sql', '127.0.0.1', UTC_TIMESTAMP());"
        fi

        # Log to SQL table `iredadmin.log`, so that global domain admins can
        # check backup status (System -> Admin Log)
        ${CMD_MYSQL} iredadmin -e "${sql_log_msg}"
    fi
done

# Append file size of backup files.
echo -e "* File size:\n----" >>${LOGFILE}
cd ${BACKUP_DIR} && \
${CMD_DU} *${TIMESTAMP}*sql* >>${LOGFILE}
echo "----" >>${LOGFILE}

echo "* Backup completed (Success? ${BACKUP_SUCCESS})." >>${LOGFILE}

if [ X"${BACKUP_SUCCESS}" == X'YES' ]; then
    echo "==> Backup completed successfully."
else
    echo -e "==> Backup completed with !!!ERRORS!!!.\n" 1>&2
fi

if [ X"${REMOVE_OLD_BACKUP}" == X'YES' -a -d ${REMOVED_BACKUP_DIR} ]; then
    echo -e "* Delete old backup: ${REMOVED_BACKUP_DIR}." >> ${LOGFILE}
    echo -e "* Suppose to delete: ${REMOVED_BACKUP_DIR}" >> ${LOGFILE}
    rm -rf ${REMOVED_BACKUP_DIR} >> ${LOGFILE} 2>&1

    sql_log_msg="INSERT INTO log (event, loglevel, msg, admin, ip, timestamp) VALUES ('backup', 'info', 'Remove old backup: ${REMOVED_BACKUP_DIR}.', 'cron_backup_sql', '127.0.0.1', UTC_TIMESTAMP());"
    ${CMD_MYSQL} iredadmin -e "${sql_log_msg}"
fi

echo "==> Detailed log (${LOGFILE}):"
echo "========================="
cat ${LOGFILE}