如何检测是否在linux机器上安装了tomcat和ant

Question

我试图在我的linux机器上安装Tomcat和Ant，但在安装之前，我只需要检查它们是否已安装。

关于tomcat的：

我GOOGLE了很多，在以下目录中搜索我的机器上为Tomcat

/usr/local/, /opt/, /usr/share/ 

但我din't找到tomcat的文件夹中的任何上述路径，是否表示tomcat未安装？所以实际上

1. what is the path to `look/find` exactly to know/check whether tomcat is installed or not in 
    all linux machines 
2. what will be the path the tomcat will be installed exactly after installation 
3. How to find the version of tomcat on any linux machine (if tomcat already installed) 
4. Whether there are any commands to look for both whether `tomcat` installed and `ant` 
    installed 

关于蚂蚁：

我用Google搜索，并得到了下面的命令，由于这是我得到了下面的结果来执行 它

sh-4.2$ ant -v 

结果

后

sh-4.2$ ant -v 
Apache Ant(TM) version 1.8.2 compiled on November 21 2011 
Trying the default build file: build.xml 
Buildfile: build.xml does not exist! 
Build failed 

所以实际上

1. Does the above result mean that `Ant` is installed ? or not ? 
2. what is the path to `look/find` exactly to know/check whether ant is installed or not in 
    all linux machines 
3. what will be the path the `ant` will be installed exactly after installation 
4. How to find the version of `Ant` on any linux machine (if Ant already installed) 

Answer 1

一般情况下，你可以检查他们是否在$ PATH，如果它们不在$ PATH，安装一个。

蚂蚁：

ant -v代表冗长，ant -version打印出它的版本。

-help, -h 
      print help on the command line options 

    -projecthelp, -p 
      gives information on possible targets for this project 

    -version 
      prints the version number and then exits ant 

    -quiet, -q 
      be extra quiet 

    -verbose, -v 
      be extra verbose 

    -debug, -d 
      print debugging information 

    -emacs, -e 
      produce logging information without adornments 

    -logfile <file>, -l <file> 
      use the given file to output log to 

    -logger <classname> 
      the class which is to perform logging 

    -listener <classname> 
      add an instance of the given class as a project listener 

    -noinput 
      do not allow interactive input 

    -buildfile <file>, -file <file>, -f <file> 
      use the given buildfile instead of the default build.xml file. 
      This is the ant equivalent of Makefile 

    -D<property>=<value> 
      use value for the given property 

    -keep-going, -k 
      execute all targets that do not depend on failed target(s) 

    -propertyfile <file> 
      load all properties from file with -D properties taking prece- 
      dence 

    -inputhandler <class> 
      the class which will handle input requests 

    -find <file>, -s <file> 
      (s)earch for buildfile towards the root of the filesystem and 
      use it 

    -nice number 
      A niceness value for the main thread: 1 (lowest) to 10 (high- 
      est); 5 is the default 

    -nouserlib 
      Run ant without using the jar files from ${user.home}/.ant/lib 

    -noclasspath 
      Run ant without using CLASSPATH 

    -autoproxy 
      Java 1.5+ : use the OS proxies 

    -main <class> 
      override ant's normal entry point 

为Tomcat：

如果Tomcat/bin目录上的$ PATH变量，version.sh将打印出的版本。