inux系统alternatives使用(java,javac,jar)

本文介绍如何使用alternatives命令配置多个Java版本共存,并通过具体示例展示了如何安装和选择不同的Java编译器。

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[host@localhost ~]$ alternatives --help

alternatives version 1.3.44 - Copyright (C) 2001 Red Hat, Inc.

This may be freely redistributed under the terms of the GNU Public License.

 

usage: alternatives --install <link> <name> <path> <priority>

                    [--initscript <service>]

                    [--slave <link> <name> <path>]*

       alternatives --remove <name> <path>

       alternatives --auto <name>

       alternatives --config <name>

       alternatives --display <name>

       alternatives --set <name> <path>

 

common options: --verbose --test --help --usage --version

                --altdir <directory> --admindir <directory>

 

[例1]

 

alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.5.0_21/jre/bin/java 3

 

[host@localhost android_eclair]$ update-alternatives --config java

 

There are 3 programs which provide 'java'.

 

  Selection    Command

-----------------------------------------------

*  1           /usr/lib/jvm/jre-1.6.0-openjdk/bin/java

   2           /usr/lib/jvm/jre-1.5.0-gcj/bin/java

 + 3           /usr/lib/jvm/jdk1.5.0_21/jre/bin/java

 

[例2]

 

alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.5.0_21/bin/javac 2

 

[host@localhost android_eclair]$ update-alternatives --config javac

 

There are 2 programs which provide 'javac'.

 

  Selection    Command

-----------------------------------------------

*  1           /usr/lib/jvm/java-1.6.0-openjdk/bin/javac

 + 2           /usr/lib/jvm/jdk1.5.0_21/bin/javac

 

[host@localhost jvm]$ ls /usr/bin/j* -l

-rwxr-xr-x 1 root root 21068 2009-11-05 04:54 /usr/bin/jackd

-rwxr-xr-x 1 root root  7420 2009-11-05 04:54 /usr/bin/jack_freewheel

-rwxr-xr-x 1 root root  9408 2009-11-05 04:54 /usr/bin/jack_load

-rwxr-xr-x 1 root root  7508 2009-11-05 04:54 /usr/bin/jack_unload

lrwxrwxrwx 1 root root    21 2010-04-28 07:41 /usr/bin/jar -> /etc/alternatives/jar 

lrwxrwxrwx 1 root root    27 2010-04-28 07:41 /usr/bin/jarsigner -> /etc/alternatives/jarsigner

lrwxrwxrwx 1 root root    22 2010-02-08 16:59 /usr/bin/java -> /etc/alternatives/java

lrwxrwxrwx 1 root root    23 2010-04-28 07:41 /usr/bin/javac -> /etc/alternatives/javac

lrwxrwxrwx 1 root root    25 2010-04-28 07:41 /usr/bin/javadoc -> /etc/alternatives/javadoc

lrwxrwxrwx 1 root root    23 2010-04-28 07:41 /usr/bin/javah -> /etc/alternatives/javah

lrwxrwxrwx 1 root root    23 2010-04-28 07:41 /usr/bin/javap -> /etc/alternatives/javap 

lrwxrwxrwx 1 root root    26 2010-04-28 07:41 /usr/bin/jconsole -> /etc/alternatives/jconsole

lrwxrwxrwx 1 root root    21 2010-04-28 07:41 /usr/bin/jdb -> /etc/alternatives/jdb

-rwxr-xr-x 1 root root   541 2009-07-26 21:02 /usr/bin/jh2indexer

-rwxr-xr-x 1 root root   538 2009-07-26 21:02 /usr/bin/jh2search

lrwxrwxrwx 1 root root    22 2010-04-28 07:41 /usr/bin/jhat -> /etc/alternatives/jhat

lrwxrwxrwx 1 root root    23 2010-04-28 07:41 /usr/bin/jinfo -> /etc/alternatives/jinfo

lrwxrwxrwx 1 root root    22 2010-04-28 07:41 /usr/bin/jmap -> /etc/alternatives/jmap

-rwxr-xr-x 1 root root 40644 2009-09-22 22:01 /usr/bin/join

-rwxr-xr-x 1 root root 23540 2009-07-27 02:21 /usr/bin/jpegicc

-rwxr-xr-x 1 root root 23288 2009-07-27 04:51 /usr/bin/jpegtran

lrwxrwxrwx 1 root root    21 2010-04-28 07:41 /usr/bin/jps -> /etc/alternatives/jps

lrwxrwxrwx 1 root root    28 2010-04-28 07:41 /usr/bin/jrunscript -> /etc/alternatives/jrunscript

lrwxrwxrwx 1 root root    27 2010-04-28 07:41 /usr/bin/jsadebugd -> /etc/alternatives/jsadebugd

-rwxr-xr-x 1 root root  8168 2009-08-10 17:16 /usr/bin/jsattach

-rwxr-xr-x 1 root root 15820 2009-08-10 17:16 /usr/bin/jscal

lrwxrwxrwx 1 root root    24 2010-04-28 07:41 /usr/bin/jstack -> /etc/alternatives/jstack

lrwxrwxrwx 1 root root    23 2010-04-28 07:41 /usr/bin/jstat -> /etc/alternatives/jstat

lrwxrwxrwx 1 root root    24 2010-04-28 07:41 /usr/bin/jstatd -> /etc/alternatives/jstatd

-rwxr-xr-x 1 root root  8492 2009-08-10 17:16 /usr/bin/jstest

-rwxr-xr-x 1 root root  6688 2009-10-28 04:23 /usr/bin/jv-convert

lrwxrwxrwx 1 root root    27 2010-04-28 07:41 /usr/bin/jvisualvm -> /etc/alternatives/jvisualvm

-rwxr-xr-x 1 root root  1757 2006-09-20 03:55 /usr/bin/jvmjar

-rwxr-xr-x 1 root root 64388 2009-09-03 17:16 /usr/bin/jwhois

 

[host@localhost jvm]$ ls -l /etc/alternatives/java*

lrwxrwxrwx 1 root root 37 2010-02-08 16:59 /etc/alternatives/java -> /usr/lib/jvm/jdk1.5.0_21/jre/bin/java

lrwxrwxrwx 1 root root 41 2010-04-28 07:41 /etc/alternatives/javac -> /usr/lib/jvm/java-1.6.0-openjdk/bin/javac

lrwxrwxrwx 1 root root 49 2010-04-28 07:41 /etc/alternatives/javac.1.gz -> /usr/share/man/man1/javac-java-1.6.0-openjdk.1.gz

lrwxrwxrwx 1 root root 43 2010-04-28 07:41 /etc/alternatives/javadoc -> /usr/lib/jvm/java-1.6.0-openjdk/bin/javadoc

lrwxrwxrwx 1 root root 51 2010-04-28 07:41 /etc/alternatives/javadoc.1.gz -> /usr/share/man/man1/javadoc-java-1.6.0-openjdk.1.gz

lrwxrwxrwx 1 root root 41 2010-04-28 07:41 /etc/alternatives/javah -> /usr/lib/jvm/java-1.6.0-openjdk/bin/javah

lrwxrwxrwx 1 root root 49 2010-04-28 07:41 /etc/alternatives/javah.1.gz -> /usr/share/man/man1/javah-java-1.6.0-openjdk.1.gz

lrwxrwxrwx 1 root root 41 2010-04-28 07:41 /etc/alternatives/javap -> /usr/lib/jvm/java-1.6.0-openjdk/bin/javap

lrwxrwxrwx 1 root root 49 2010-04-28 07:41 /etc/alternatives/javap.1.gz -> /usr/share/man/man1/javap-java-1.6.0-openjdk.1.gz

lrwxrwxrwx 1 root root 31 2010-04-28 07:41 /etc/alternatives/java_sdk -> /usr/lib/jvm/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 31 2010-04-28 07:41 /etc/alternatives/java_sdk_1.6.0 -> /usr/lib/jvm/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 39 2010-04-28 07:41 /etc/alternatives/java_sdk_1.6.0_exports -> /usr/lib/jvm-exports/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 39 2010-04-28 07:41 /etc/alternatives/java_sdk_exports -> /usr/lib/jvm-exports/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 31 2010-04-28 07:41 /etc/alternatives/java_sdk_openjdk -> /usr/lib/jvm/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 39 2010-04-28 07:41 /etc/alternatives/java_sdk_openjdk_exports -> /usr/lib/jvm-exports/java-1.6.0-openjdk 

[host@localhost jvm]$ ls -l /etc/alternatives/jre*

lrwxrwxrwx 1 root root 26 2010-04-28 05:24 /etc/alternatives/jre_1.5.0 -> /usr/lib/jvm/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 34 2010-04-28 05:24 /etc/alternatives/jre_1.5.0_exports -> /usr/lib/jvm-exports/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 30 2010-04-28 07:41 /etc/alternatives/jre_1.6.0 -> /usr/lib/jvm/jre-1.6.0-openjdk

lrwxrwxrwx 1 root root 38 2010-04-28 07:41 /etc/alternatives/jre_1.6.0_exports -> /usr/lib/jvm-exports/jre-1.6.0-openjdk

lrwxrwxrwx 1 root root 26 2010-04-28 05:24 /etc/alternatives/jre_gcj -> /usr/lib/jvm/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 34 2010-04-28 05:24 /etc/alternatives/jre_gcj_exports -> /usr/lib/jvm-exports/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 30 2010-04-28 07:41 /etc/alternatives/jre_openjdk -> /usr/lib/jvm/jre-1.6.0-openjdk

lrwxrwxrwx 1 root root 38 2010-04-28 07:41 /etc/alternatives/jre_openjdk_exports -> /usr/lib/jvm-exports/jre-1.6.0-openjdk

 

执行例子1,2后:

[host@localhost jvm]$ ls -l /etc/alternatives/java*

lrwxrwxrwx 1 root root 37 2010-02-08 16:59 /etc/alternatives/java -> /usr/lib/jvm/jdk1.5.0_21/jre/bin/java

lrwxrwxrwx 1 root root 34 2010-02-08 17:25 /etc/alternatives/javac -> /usr/lib/jvm/jdk1.5.0_21/bin/javac

lrwxrwxrwx 1 root root 31 2010-04-28 07:41 /etc/alternatives/java_sdk_1.6.0 -> /usr/lib/jvm/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 39 2010-04-28 07:41 /etc/alternatives/java_sdk_1.6.0_exports -> /usr/lib/jvm-exports/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 31 2010-04-28 07:41 /etc/alternatives/java_sdk_openjdk -> /usr/lib/jvm/java-1.6.0-openjdk

lrwxrwxrwx 1 root root 39 2010-04-28 07:41 /etc/alternatives/java_sdk_openjdk_exports -> /usr/lib/jvm-exports/java-1.6.0-openjdk

 

 

[host@localhost jvm]$ ls -l /etc/alternatives/jre*

lrwxrwxrwx 1 root root 26 2010-04-28 05:24 /etc/alternatives/jre_1.5.0 -> /usr/lib/jvm/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 34 2010-04-28 05:24 /etc/alternatives/jre_1.5.0_exports -> /usr/lib/jvm-exports/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 30 2010-04-28 07:41 /etc/alternatives/jre_1.6.0 -> /usr/lib/jvm/jre-1.6.0-openjdk

lrwxrwxrwx 1 root root 38 2010-04-28 07:41 /etc/alternatives/jre_1.6.0_exports -> /usr/lib/jvm-exports/jre-1.6.0-openjdk

lrwxrwxrwx 1 root root 26 2010-04-28 05:24 /etc/alternatives/jre_gcj -> /usr/lib/jvm/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 34 2010-04-28 05:24 /etc/alternatives/jre_gcj_exports -> /usr/lib/jvm-exports/jre-1.5.0-gcj

lrwxrwxrwx 1 root root 30 2010-04-28 07:41 /etc/alternatives/jre_openjdk -> /usr/lib/jvm/jre-1.6.0-openjdk

lrwxrwxrwx 1 root root 38 2010-04-28 07:41 /etc/alternatives/jre_openjdk_exports -> /usr/lib/jvm-exports/jre-1.6.0-openjdk

### 在Linux系统中设置和使用Flameshot截图工具 #### 安装Flameshot 在Linux系统中,可以通过包管理器安装Flameshot。以下是一些常见的Linux发行版的安装方法: 对于基于Debian的系统(如Ubuntu),可以使用以下命令安装: ```bash sudo apt update sudo apt install flameshot ``` 对于基于Red Hat的系统(如Fedora),可以使用以下命令安装: ```bash sudo dnf install flameshot ``` 对于Arch Linux及其衍生版本,可以使用以下命令安装: ```bash sudo pacman -S flameshot ``` 如果发行版的官方仓库中没有Flameshot,也可以从源代码编译安装或通过Flatpak安装[^1]。 #### 配置Flameshot 安装完成后,可以通过以下方式进行配置: 1. **设置快捷键** Flameshot本身不提供快捷键功能,但可以通过操作系统的快捷键设置来绑定Flameshot的启动命令。例如,在Ubuntu中,可以通过“设置” -> “键盘快捷键” -> “自定义快捷键”添加一个新的快捷键,并将命令设置为`flameshot gui`[^2]。 2. **CLI模式配置** 如果需要从命令行使用Flameshot,可以使用其丰富的命令行选项。例如,捕获整个屏幕并保存到指定路径: ```bash flameshot full -p /path/to/save/screenshot.png ``` 3. **自定义截图区域** 使用`flameshot gui`命令可以启动图形界面,允许用户手动选择截图区域。 #### 使用Flameshot Flameshot提供了多种截图方式,以下是常用的几种用法: 1. **捕获整个屏幕** 使用以下命令捕获整个屏幕: ```bash flameshot full ``` 2. **捕获选定区域** 使用以下命令捕获用户选择的区域: ```bash flameshot screen ``` 3. **捕获活动窗口** 使用以下命令捕获当前活动窗口: ```bash flameshot win ``` 4. **编辑和分享截图** Flameshot内置了简单的图像编辑功能,可以直接在截图上进行标注、绘制形状等操作。此外,还可以将截图直接上传到图片托管服务。 ### 注意事项 确保Flameshot已正确安装并且系统路径中可用。如果遇到任何问题,可以检查Flameshot的日志文件以获取更多信息。
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