一般通过默认安装的ubuntu是不能解压rar文件的，只有在安装了rar解压工具之后，才可以解压。其实在ubuntu下安装rar解压工具是非常简单的，只需要两个步骤就可以迅速搞定。
ubuntu 下rar解压工具安装方法：
压缩功能
安装 sudo apt-get install rar
卸载 sudo apt-get remove rar
解压功能
安装 sudo apt-get install unrar
卸载 sudo apt-get remove unrar
ubuntu解压命令全览
.tar
解包：tar xvf FileName.tar
打包：tar cvf FileName.tar DirName
注：tar是打包，不是压缩！
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.gz
解压1：gunzip FileName.gz
解压2：gzip -d FileName.gz
压缩：gzip FileName
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.tar.gz 和 .tgz
解压：tar zxvf FileName.tar.gz
压缩：tar zcvf FileName.tar.gz DirName
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.bz2
解压1：bzip2 -d FileName.bz2
解压2：bunzip2 FileName.bz2
压缩： bzip2 -z FileName
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.tar.bz2
解压：tar jxvf FileName.tar.bz2
压缩：tar jcvf FileName.tar.bz2 DirName
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.bz
解压1：bzip2 -d FileName.bz
解压2：bunzip2 FileName.bz
压缩：未知
.tar.bz
解压：tar jxvf FileName.tar.bz
压缩：未知
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.Z
解压：uncompress FileName.Z
压缩：compress FileName
.tar.Z
解压：tar Zxvf FileName.tar.Z
压缩：tar Zcvf FileName.tar.Z DirName
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.zip
解压：unzip FileName.zip
压缩：zip FileName.zip DirName
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.rar
解压：rar x FileName.rar
压缩：rar a FileName.rar DirName
rar请到：http://www.rarsoft.com/download.htm 下载！
解压后请将rar_static拷贝到/usr/bin目录（其他由$PATH环境变量指定的目录也可以）：
[root@www2 tmp]# cp rar_static /usr/bin/rar
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.lha
解压：lha -e FileName.lha
压缩：lha -a FileName.lha FileName
lha请到：http://www.infor.kanazawa-it.ac.jp/~ishii/lhaunix/下载！
>解压后请将lha拷贝到/usr/bin目录（其他由$PATH环境变量指定的目录也可以）：
[root@www2 tmp]# cp lha /usr/bin/
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.rpm
解包：rpm2cpio FileName.rpm | cpio -div
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.deb
解包：ar p FileName.deb data.tar.gz | tar zxf -
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tar .tgz .tar.gz .tar.Z .tar.bz .tar.bz2 .zip .cpio .rpm .deb .slp .arj .rar .ace .lha .lzh .lzx .lzs .arc .sda .sfx .lnx .zoo .cab .kar .cpt .pit .sit .sea
解压：sEx x FileName.*
压缩：sEx a FileName.* FileName