tomcat运行控制脚本catalina.sh分析

分析catalina.sh脚本的目的，一个是学习脚本中shell的各类用法，还有就是为编写tomcat多服务器远程启动脚本做准备，实现版本上线自动化无人干预部署，此前作者已发表" tomcat变量环境脚本setclasspath.sh分析"来为此篇作为铺垫，需要两篇文章一起看，才能全面的分析出tomcat的启动过程。

tomcat版本：6.0.35

#!/bin/sh# Licensed to the Apache Software Foundation (ASF) under one or more# contributor license agreements.  See the NOTICE file distributed with# this work for additional information regarding copyright ownership.# The ASF licenses this file to You under the Apache License, Version 2.0# (the "License"); you may not use this file except in compliance with# the License.  You may obtain a copy of the License at##     http://www.apache.org/licenses/LICENSE-2.0## Unless required by applicable law or agreed to in writing, software# distributed under the License is distributed on an "AS IS" BASIS,# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.# See the License for the specific language governing permissions and# limitations under the License.# -----------------------------------------------------------------------------# Start/Stop Script for the CATALINA Server## Environment Variable Prerequisites##   CATALINA_HOME   May point at your Catalina "build" directory.##   CATALINA_BASE   (Optional) Base directory for resolving dynamic portions#                   of a Catalina installation.  If not present, resolves to#                   the same directory that CATALINA_HOME points to.##   CATALINA_OUT    (Optional) Full path to a file where stdout and stderr#                   will be redirected.#                   Default is $CATALINA_BASE/logs/catalina.out##   CATALINA_OPTS   (Optional) Java runtime options used when the "start",#                   or "run" command is executed.##   CATALINA_TMPDIR (Optional) Directory path location of temporary directory#                   the JVM should use (java.io.tmpdir).  Defaults to#                   $CATALINA_BASE/temp.##   JAVA_HOME       Must point at your Java Development Kit installation.#                   Required to run the with the "debug" argument.##   JRE_HOME        Must point at your Java Development Kit installation.#                   Defaults to JAVA_HOME if empty.##   JAVA_OPTS       (Optional) Java runtime options used when the "start",#                   "stop", or "run" command is executed.##   JAVA_ENDORSED_DIRS (Optional) Lists of of colon separated directories#                   containing some jars in order to allow replacement of APIs#                   created outside of the JCP (i.e. DOM and SAX from W3C).#                   It can also be used to update the XML parser implementation.#                   Defaults to $CATALINA_HOME/endorsed.##   JPDA_TRANSPORT  (Optional) JPDA transport used when the "jpda start"#                   command is executed. The default is "dt_socket".##   JPDA_ADDRESS    (Optional) Java runtime options used when the "jpda start"#                   command is executed. The default is 8000.##   JPDA_SUSPEND    (Optional) Java runtime options used when the "jpda start"#                   command is executed. Specifies whether JVM should suspend#                   execution immediately after startup. Default is "n".##   JPDA_OPTS       (Optional) Java runtime options used when the "jpda start"#                   command is executed. If used, JPDA_TRANSPORT, JPDA_ADDRESS,#                   and JPDA_SUSPEND are ignored. Thus, all required jpda#                   options MUST be specified. The default is:##                   -agentlib:jdwp=transport=$JPDA_TRANSPORT,#                       address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND##   CATALINA_PID    (Optional) Path of the file which should contains the pid#                   of catalina startup java process, when start (fork) is used##   LOGGING_CONFIG  (Optional) Override Tomcat's logging config file#                   Example (all one line)#                   LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties"##   LOGGING_MANAGER (Optional) Override Tomcat's logging manager#                   Example (all one line)#                   LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"## $Id: catalina.sh 1146097 2011-07-13 15:25:05Z markt $# -----------------------------------------------------------------------------export JRE_HOME=/usr/java/jdk1.6.0_38export CATALINA_HOME=/home/xrltest1/tomcatJAVA_OPTS="-server -Xms2048m -Xmx2048m -Xmn768m -XX:PermSize=128m -XX:MaxPermSize=256m -XX:+UseParallelOldGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/home/xrltest1/tomcat/dumpfile/heap.bin  -Xloggc:/home/xrltest1/tomcat/logs/gc.log"#作者添加的环境申明，如果一台服务器中有多台tomcat要使用不同版本的JVM，就可以直接这这边添加JRE_HOME，不需要再/etc/profile.d中再配置JRE_HOME环境变量# OS specific support.  $var _must_ be set to either true or false.#此处语句判断操作系统，同时对操作系统支持#os400是 IBM的AIX#darwin是MacOSX 操作环境的操作系统成份#Darwin是windows平台上运行的类UNIX模拟环境cygwin=falseos400=falsedarwin=falsecase "`uname`" inCYGWIN*) cygwin=true;;OS400*) os400=true;;Darwin*) darwin=true;;esac# resolve links - $0 may be a softlink#此处的RPG抓取的是文件名，因为可能是符号链接，所以下面循环语句的作用就是找到文件真实源路径PRG="$0"while [ -h "$PRG" ]; do  ls=`ls -ld "$PRG"`  link=`expr "$ls" : '.*-> \(.*\)$'`  if expr "$link" : '/.*' > /dev/null; then    PRG="$link"  else    PRG=`dirname "$PRG"`/"$link"  fidone#获取脚本目录真实目录地址# Get standard environment variablesPRGDIR=`dirname "$PRG"`# Only set CATALINA_HOME if not already set[ -z "$CATALINA_HOME" ] && CATALINA_HOME=`cd "$PRGDIR/.." >/dev/null; pwd`# Copy CATALINA_BASE from CATALINA_HOME if not already set[ -z "$CATALINA_BASE" ] && CATALINA_BASE="$CATALINA_HOME"#上面两个语句判断变量$CATALINA_HOME和$CATALINA_BASE是否存在，不存在则给予附值#CATALINA_BASE="$CATALINA_HOME"# Ensure that any user defined CLASSPATH variables are not used on startup,# but allow them to be specified in setenv.sh, in rare case when it is needed.CLASSPATH=#test -r File 文件存在并且可读if [ -r "$CATALINA_BASE/bin/setenv.sh" ]; then  . "$CATALINA_BASE/bin/setenv.sh"elif [ -r "$CATALINA_HOME/bin/setenv.sh" ]; then  . "$CATALINA_HOME/bin/setenv.sh"fi#默认的tomcat的bin目录下没有这个文件，可以自行编写setenv.sh这个文件设定环境变量# For Cygwin, ensure paths are in UNIX format before anything is touchedif $cygwin; then  [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`  [ -n "$JRE_HOME" ] && JRE_HOME=`cygpath --unix "$JRE_HOME"`  [ -n "$CATALINA_HOME" ] && CATALINA_HOME=`cygpath --unix "$CATALINA_HOME"`  [ -n "$CATALINA_BASE" ] && CATALINA_BASE=`cygpath --unix "$CATALINA_BASE"`  [ -n "$CLASSPATH" ] && CLASSPATH=`cygpath --path --unix "$CLASSPATH"`fi# For OS400if $os400; then  # Set job priority to standard for interactive (interactive - 6) by using  # the interactive priority - 6, the helper threads that respond to requests  # will be running at the same priority as interactive jobs.  COMMAND='chgjob job('$JOBNAME') runpty(6)'  system $COMMAND  # Enable multi threading  export QIBM_MULTI_THREADED=Yfi# Get standard Java environment variablesif $os400; then  # -r will Only work on the os400 if the files are:  # 1. owned by the user  # 2. owned by the PRIMARY group of the user  # this will not work if the user belongs in secondary groups  BASEDIR="$CATALINA_HOME"  . "$CATALINA_HOME"/bin/setclasspath.shelse  #这点一定要注意了，本脚本中没有赋值却突然冒出的变量  #都是在setclasspath.sh这个脚本中执行赋值的。比如$_RUNJAVA  #作者会在下一篇文章中，分析setclasspath.sh这个脚本  if [ -r "$CATALINA_HOME"/bin/setclasspath.sh ]; then    BASEDIR="$CATALINA_HOME"    . "$CATALINA_HOME"/bin/setclasspath.sh  else    echo "Cannot find $CATALINA_HOME/bin/setclasspath.sh"    echo "This file is needed to run this program"    exit 1  fifi#以上是出现在其他操作环境下的脚本的可用性设置，因默认linux系统，上面就不做解读了if [ -z "$CATALINA_BASE" ] ; then  CATALINA_BASE="$CATALINA_HOME"fi#将变量赋值# Add tomcat-juli.jar and bootstrap.jar to classpath# tomcat-juli.jar can be over-ridden per instanceif [ ! -z "$CLASSPATH" ] ; then  CLASSPATH="$CLASSPATH":fi#虽然前面已将做出CATALINA_BASE="$CATALINA_HOME"的语句#此处还是添加了判断，增强了代码的健壮性#添加变量$CLASSPATH的值if [ "$CATALINA_BASE" != "$CATALINA_HOME" ] && [ -r "$CATALINA_BASE/bin/tomcat-juli.jar" ] ; then  CLASSPATH="$CLASSPATH""$CATALINA_BASE"/bin/tomcat-juli.jar:"$CATALINA_HOME"/bin/bootstrap.jarelse  CLASSPATH="$CLASSPATH""$CATALINA_HOME"/bin/bootstrap.jarfi#确认日志路径$CATALINA_OUT#这部分主要判断这些变量是否预定义，有就以预定义为主，没有就设置为默认格式if [ -z "$CATALINA_OUT" ] ; then  CATALINA_OUT="$CATALINA_BASE"/logs/catalina.outfiif [ -z "$CATALINA_TMPDIR" ] ; then  # Define the java.io.tmpdir to use for Catalina  CATALINA_TMPDIR="$CATALINA_BASE"/tempfi# Bugzilla 37848: When no TTY is available, don't output to console#获取当前shell运行的终端设备have_tty=0if [ "`tty`" != "not a tty" ]; then    have_tty=1fi# For Cygwin, switch paths to Windows format before running javaif $cygwin; then  JAVA_HOME=`cygpath --absolute --windows "$JAVA_HOME"`  JRE_HOME=`cygpath --absolute --windows "$JRE_HOME"`  CATALINA_HOME=`cygpath --absolute --windows "$CATALINA_HOME"`  CATALINA_BASE=`cygpath --absolute --windows "$CATALINA_BASE"`  CATALINA_TMPDIR=`cygpath --absolute --windows "$CATALINA_TMPDIR"`  CLASSPATH=`cygpath --path --windows "$CLASSPATH"`  JAVA_ENDORSED_DIRS=`cygpath --path --windows "$JAVA_ENDORSED_DIRS"`fi# Set juli LogManager config file if it is present and an override has not been issued#确认$LOGGING_CONFIG变量if [ -z "$LOGGING_CONFIG" ]; then  if [ -r "$CATALINA_BASE"/conf/logging.properties ]; then    LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties"  else    # Bugzilla 45585    LOGGING_CONFIG="-Dnop"  fifi#确认$LOGGING_MANAGER变量if [ -z "$LOGGING_MANAGER" ]; then  JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"else  JAVA_OPTS="$JAVA_OPTS $LOGGING_MANAGER"fi# ----- Execute The Requested Command -----------------------------------------# Bugzilla 37848: only output this if we have a TTY#正常情况下have_tty=1if [ $have_tty -eq 1 ]; then  echo "Using CATALINA_BASE:   $CATALINA_BASE"  echo "Using CATALINA_HOME:   $CATALINA_HOME"  echo "Using CATALINA_TMPDIR: $CATALINA_TMPDIR"  if [ "$1" = "debug" ] ; then     echo "Using JAVA_HOME:       $JAVA_HOME"  else     echo "Using JRE_HOME:        $JRE_HOME"  fi      echo "Using CLASSPATH:       $CLASSPATH"  #以下这句判断设置的$CATALINA_PID变量如果不存在，则显示"Using CATALINA_PID:    $CATALINA_PID"，如果存在则不显示  if [ ! -z "$CATALINA_PID" ]; then    echo "Using CATALINA_PID:    $CATALINA_PID"  fifi#以上就是在启动tomcat是输出的环境变量信息##获取第一次参数，jpda在后面的说明为：jpda start        Start Catalina under JPDA debuggerif [ "$1" = "jpda" ] ; then  if [ -z "$JPDA_TRANSPORT" ]; thenJPDA_TRANSPORT="dt_socket"  fi  if [ -z "$JPDA_ADDRESS" ]; thenJPDA_ADDRESS="8000"  fi  if [ -z "$JPDA_SUSPEND" ]; thenJPDA_SUSPEND="n"  fi  if [ -z "$JPDA_OPTS" ]; thenJPDA_OPTS="-agentlib:jdwp=transport=$JPDA_TRANSPORT,address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND"  fi  CATALINA_OPTS="$CATALINA_OPTS $JPDA_OPTS"  shiftfi#JPDA 模式是开启远程debug模式，端口就是JPDA_ADDRESS,生产环境用不到，不去深入#这个是debug模式#值得注意的是变量$_RUNJDB，居然在全文没有找到赋值的语句。#从这边开始就注意了，里面的if-fi判断很多，一定要先调好格式再看if [ "$1" = "debug" ] ; thenif $os400; thenecho "Debug command not available on OS400"exit 1elseshiftif [ "$1" = "-security" ] ; then  if [ $have_tty -eq 1 ]; thenecho "Using Security Manager"  fi  shift  exec "$_RUNJDB" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \-Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \-sourcepath "$CATALINA_HOME"/../../java \-Djava.security.manager \-Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \-Dcatalina.base="$CATALINA_BASE" \-Dcatalina.home="$CATALINA_HOME" \-Djava.io.tmpdir="$CATALINA_TMPDIR" \org.apache.catalina.startup.Bootstrap "$@" startelse  exec "$_RUNJDB" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \-Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \-sourcepath "$CATALINA_HOME"/../../java \-Dcatalina.base="$CATALINA_BASE" \-Dcatalina.home="$CATALINA_HOME" \-Djava.io.tmpdir="$CATALINA_TMPDIR" \org.apache.catalina.startup.Bootstrap "$@" startfi    fi   #上面语句是适配AIX环境的，不做解读  #当参数是debug时  elif [ "$1" = "run" ]; thenshift#当使用shift命令之后，原来的$2会变成$1，并且原有的$1变得不可用，通过$#命令获得的参数个数也会少1#这样就可以使用$1获取第二个参数  if [ "$1" = "-security" ] ; thenif [ $have_tty -eq 1 ]; then  echo "Using Security Manager"fishift#作废掉前两个参数exec "$_RUNJAVA" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \  -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \  -Djava.security.manager \  -Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \  -Dcatalina.base="$CATALINA_BASE" \  -Dcatalina.home="$CATALINA_HOME" \  -Djava.io.tmpdir="$CATALINA_TMPDIR" \  org.apache.catalina.startup.Bootstrap "$@" start  elseexec "$_RUNJAVA" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \  -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \  -Dcatalina.base="$CATALINA_BASE" \  -Dcatalina.home="$CATALINA_HOME" \  -Djava.io.tmpdir="$CATALINA_TMPDIR" \  org.apache.catalina.startup.Bootstrap "$@" start#这个命令其实就是java命令，指定org.apache.catalina.startup.Bootstrap 这个class文件，$@和"start"作用类似于传参到前面的安格class里  fi#正式进入启动的过程啦~elif [ "$1" = "start" ] ; then  if [ ! -z "$CATALINA_PID" ]; then  #test -z 字符串 字符串的长度为零 ,判断这个变量或者文件内有数据if [ -f "$CATALINA_PID" ]; then#-f 该『文件名』是否为文件(file)？(常用)  if [ -s "$CATALINA_PID" ]; then  #-s 侦测该文件名是否为『非空白文件』？echo "Existing PID file found during start."if [ -r "$CATALINA_PID" ]; then#-r 侦测该文件名是否具有『可读』的属性？#以上if语句主要判断这个$CATALINA_PID，是否能正常可读  PID=`cat "$CATALINA_PID"`  ps -p $PID >/dev/null 2>&1  if [ $? -eq 0 ] ; then  #判断这个ＰＩＤ现在有没有被占用，有就输出这个tomcat依旧在运行，退出  #上面这段语句功能非常好，可以判断出这个PID是否还在运行echo "Tomcat appears to still be running with PID $PID. Start aborted."exit 1  elseecho "Removing/clearing stale PID file."rm -f "$CATALINA_PID" >/dev/null 2>&1#删除了这个$CATALINA_PID文件if [ $? != 0 ]; then  if [ -w "$CATALINA_PID" ]; then  #-w 侦测该文件名是否具有『可写』的属性？ cat /dev/null > "$CATALINA_PID"#清空$CATALINA_PID文件  else  #如果不具有可写权限，则输出信息，退出echo "Unable to remove or clear stale PID file. Start aborted."exit 1  fifi  fielse#如果"$CATALINA_PID"没有可读权限，任然输出信息退出。  echo "Unable to read PID file. Start aborted."  exit 1fi  else  #"$CATALINA_PID"是空白文件rm -f "$CATALINA_PID" >/dev/null 2>&1#强制删除$CATALINA_PID文件if [ $? != 0 ]; then#成功则进行判断，没有读权限则退出脚本  if [ ! -w "$CATALINA_PID" ]; thenecho "Unable to remove or write to empty PID file. Start aborted."exit 1  fifi  fififi#这段语句，主要目的就是清空$CATALINA_PID文件，如果出现不可读写，则输出信息退出  shift  #作废掉前面参数，$1将表示第二个参数  touch "$CATALINA_OUT"  #创建$CATALINA_OUT变量路径文件  if [ "$1" = "-security" ] ; then  #如果第二个参数是-securityif [ $have_tty -eq 1 ]; then  echo "Using Security Manager"fishift"$_RUNJAVA" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \  -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \  -Djava.security.manager \  -Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \  -Dcatalina.base="$CATALINA_BASE" \  -Dcatalina.home="$CATALINA_HOME" \  -Djava.io.tmpdir="$CATALINA_TMPDIR" \  org.apache.catalina.startup.Bootstrap "$@" start \  >> "$CATALINA_OUT" 2>&1 &  else  #我们平时执行启动tomcat核心就是这一句了  #"$_RUNJAVA" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \  -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \  -Dcatalina.base="$CATALINA_BASE" \  -Dcatalina.home="$CATALINA_HOME" \  -Djava.io.tmpdir="$CATALINA_TMPDIR" \  org.apache.catalina.startup.Bootstrap "$@" start \  >> "$CATALINA_OUT" 2>&1 &#从&可以看出启动的命令在后台启动  fiif [ ! -z "$CATALINA_PID" ]; then#判断CATALINA_PID如果不是空字符，则将Shell最后运行的后台Process的PID 传给$CATALINA_PIDecho $! > "$CATALINA_PID"#在使用命令运行进程至后台时，可以使用$!抓取前面启动运行在后台进程的进程号fifi#下面开始了tomcat停止模块了elif [ "$1" = "stop" ] ; then  shift  SLEEP=5     if [ ! -z "$1" ]; then    echo $1 | grep "[^0-9]" >/dev/null 2>&1    if [ $? -gt 0 ]; then      SLEEP=$1      shift    fi  fi  #上面语句主要是判断停止语句执行到此时，设定几秒后再执行停止语句  #用来配合stop n     FORCE=0  if [ "$1" = "-force" ]; then    shift    FORCE=1  fi  #如果参数中使用了-force，则FORCE=1    if [ ! -z "$CATALINA_PID" ]; then  #$CATALINA_PID文件不是非空    if [ -f "$CATALINA_PID" ]; then      if [ -s "$CATALINA_PID" ]; then        kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1#kill -0 pid 不发送任何信号，但是系统会进行错误检查。        if [ $? -gt 0 ]; then          echo "PID file found but no matching process was found. Stop aborted."          exit 1        fi      else        echo "PID file is empty and has been ignored."      fi    else      echo "\$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted."      exit 1    fi  fi  #以上脚本是进行停止命令检错的，如果可能停止不了，则可以直接报错    "$_RUNJAVA" $JAVA_OPTS \    -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \    -Dcatalina.base="$CATALINA_BASE" \    -Dcatalina.home="$CATALINA_HOME" \    -Djava.io.tmpdir="$CATALINA_TMPDIR" \    org.apache.catalina.startup.Bootstrap "$@" stop#这个就是停止脚本的核心命令了    if [ ! -z "$CATALINA_PID" ]; then    if [ -f "$CATALINA_PID" ]; then      while [ $SLEEP -ge 0 ]; do        kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1        if [ $? -gt 0 ]; then          rm -f "$CATALINA_PID" >/dev/null 2>&1          if [ $? != 0 ]; then            if [ -w "$CATALINA_PID" ]; then              cat /dev/null > "$CATALINA_PID"            else              echo "Tomcat stopped but the PID file could not be removed or cleared."            fi          fi          break        fi        if [ $SLEEP -gt 0 ]; then          sleep 1        fi        if [ $SLEEP -eq 0 ]; then          if [ $FORCE -eq 0 ]; then            echo "Tomcat did not stop in time. PID file was not removed."          fi        fi        SLEEP=`expr $SLEEP - 1 `      done    fi  fi  #上段语句主要是清空$CATALINA_PID    #值得注意的是，生产环境偶尔不加-force选项，tomcat有时无法停止下来  #如果参数带"-force" ，则强制kill掉tomcat  if [ $FORCE -eq 1 ]; then    if [ -z "$CATALINA_PID" ]; then      echo "Kill failed: \$CATALINA_PID not set"    else      if [ -f "$CATALINA_PID" ]; then        PID=`cat "$CATALINA_PID"`        echo "Killing Tomcat with the PID: $PID"        kill -9 $PID#强制执行的核心命令        rm -f "$CATALINA_PID" >/dev/null 2>&1        if [ $? != 0 ]; then          echo "Tomcat was killed but the PID file could not be removed."        fi      fi    fi  fi#查看版本参数elif [ "$1" = "version" ] ; then    "$_RUNJAVA"   \      -classpath "$CATALINA_HOME/lib/catalina.jar" \      org.apache.catalina.util.ServerInfoelse  echo "Usage: catalina.sh ( commands ... )"  echo "commands:"  if $os400; then    echo "  debug             Start Catalina in a debugger (not available on OS400)"    echo "  debug -security   Debug Catalina with a security manager (not available on OS400)"  else    echo "  debug             Start Catalina in a debugger"    echo "  debug -security   Debug Catalina with a security manager"  fi  echo "  jpda start        Start Catalina under JPDA debugger"  echo "  run               Start Catalina in the current window"  echo "  run -security     Start in the current window with security manager"  echo "  start             Start Catalina in a separate window"  echo "  start -security   Start in a separate window with security manager"  echo "  stop              Stop Catalina, waiting up to 5 seconds for the process to end"  echo "  stop n            Stop Catalina, waiting up to n seconds for the process to end"  echo "  stop -force       Stop Catalina, wait up to 5 seconds and then use kill -KILL if still running"  echo "  stop n -force     Stop Catalina, wait up to n seconds and then use kill -KILL if still running"  echo "  version           What version of tomcat are you running?"  echo "Note: Waiting for the process to end and use of the -force option require that \$CATALINA_PID is defined"  exit 1fi

总结下，catalina.sh脚本使用了大量的判断，使用if作为参数的输入判断，核心的启动命令其实就是java命令。如果在发生tomcat启动异常，大家就可以排查时在catalina.sh完成时出现问题，还是catalina.sh启动后出现异常，如果有想要更加深入的小伙伴，可以学习下java，会在JVM调优和排障上会走的更远。