问题背景：
root 用户安装了maven，切换到jenkins 用户可以正常执行mvn 命令，但是jenkins job 构建任务却无法执行mvn命令，报错如下：/bin/sh: 1: mvn: not found
1、root用户安装maven
root# mvn -v Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d; 2017-10-18T07:58:13Z) Maven home: /usr/share/maven Java version: 1.8.0_151, vendor: Oracle Corporation Java home: /usr/java/jdk1.8.0_151/jre Default locale: en_US, platform encoding: UTF-8 OS name: "linux", version: "3.13.0-135-generic", arch: "amd64", family: "unix"
2、root用户配置/etc/profile 文件，并source 使配置生效
export M2_HOME=/usr/share/maven
export PATH=$PATH:${M2_HOME}/bin
3、切换到ubuntu用户执行mvn命令，报错
ubuntu@$ whereis mvn mvn: /usr/bin/mvn /usr/bin/X11/mvn /usr/share/man/man1/mvn.1.gz ubuntu@$ /usr/bin/mvn -v -bash: /usr/bin/mvn: Too many levels of symbolic links
4、root用户下查看/usr/bin/mvn 软连接信息
root@# whereis mvn mvn: /usr/bin/mvn /usr/bin/X11/mvn /usr/share/man/man1/mvn.1.gz
root@# ll /usr/bin/mvn lrwxrwxrwx 1 root root 3 Dec 8 13:44 /usr/bin/mvn -> mvn
5、更改软连接方式
root@# rm -f /usr/bin/mvn root@# ln -s /usr/share/maven/bin/mvn /usr/bin/mvn root@# ll /usr/bin/mvn lrwxrwxrwx 1 root root 24 Dec 8 13:47 /usr/bin/mvn -> /usr/share/maven/bin/mvn*
6、ubuntu用户下再次验证
ubuntu@$ mvn -v Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d; 2017-10-18T07:58:13Z) Maven home: /usr/share/maven Java version: 1.8.0_151, vendor: Oracle Corporation Java home: /usr/java/jdk1.8.0_151/jre Default locale: en_US, platform encoding: UTF-8 OS name: "linux", version: "3.13.0-135-generic", arch: "amd64", family: "unix"
总结：
建立软连接的时候，尽量采用绝对路径，避免采用相对路径建立软链接。