我知道我可以通过执行命令来获得帮助man openssl。是否有可能以某种方式仅通过openssl req命令获得帮助？
我已经在自签名安全Mosquitto服务器上生成了客户端密钥证书。我已将带有客户端密钥的 CA 和客户端证书复制到客户端计算机中。客户端订阅运行良好：
mosquitto_sub -h 192.168.1.8 -t sensor --cafile ca.crt --cert client.crt --key client.key -p 8883 -d
但是，如果有人破解了我的客户端机器并获得了凭据怎么办。如何在服务器机器中禁用此证书？
我的 Debian Lenny 系统中有静态 IP，通过 IP ping Internet 工作正常。遗憾的是 www.google.com 未按名称解析。我无法在我的 Linux 上安装任何附加软件，因为它不解析名称。
/etc/网络/接口：
# Used by ifup(8) and ifdown(8). See the interfaces(5) manpage or
# /usr/share/doc/ifupdown/examples for more information.
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface uses static address
auto eth0
iface eth0 inet static
address 192.168.1.99
netmask 255.255.255.0
broadcast 192.168.1.255
network 192.168.1.0
gateway 192.168.1.1
dns-nameservers 8.8.8.8
如何使用标准工具跟踪 DNS 请求以发现问题？
我在 Windows 中使用 putty 客户端通过 SSH 连接到远程 Debian 6。如果我以 root 身份登录，我有正常的命令提示符，root@ion:~#并且在按下时命令自动完成工作正常tab。如果我以非 root 用户身份登录，我只能$在命令提示符下使用，而没有命令自动完成功能。
为什么会这样以及如何扩展非 root 用户的可能性？
尝试将 Oracle Java 6 SDK 安装到 Debian Lenny。我已经下载了 rpm 文件。执行命令后
rpm -ivh jdk-6u45-linux-i586.rpm sun-javadb-core-10.6.2-1.1.i386.rpm sun-javadb-demo-10.6.2-1.1.i386.rpm sun-javadb-docs-10.6.2-1.1.i386.rpm sun-javadb-javadoc-10.6.2-1.1.i386.rpm sun-javadb-client-10.6.2-1.1.i386.rpm
得到输出：
/bin/basename is needed by jdk-1.6.0_45-fcs.i586
/bin/cat is needed by jdk-1.6.0_45-fcs.i586
/bin/cp is needed by jdk-1.6.0_45-fcs.i586
/bin/gawk is needed by jdk-1.6.0_45-fcs.i586
/bin/grep is needed by jdk-1.6.0_45-fcs.i586
/bin/ln is needed by jdk-1.6.0_45-fcs.i586
/bin/ls is needed by jdk-1.6.0_45-fcs.i586
/bin/mkdir is needed by jdk-1.6.0_45-fcs.i586
/bin/mv is needed by jdk-1.6.0_45-fcs.i586
/bin/pwd is needed by jdk-1.6.0_45-fcs.i586
/bin/rm is needed by jdk-1.6.0_45-fcs.i586
/bin/sed is needed by jdk-1.6.0_45-fcs.i586
/bin/sort is needed by jdk-1.6.0_45-fcs.i586
/bin/touch is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/cut is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/dirname is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/expr is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/find is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/tail is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/tr is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/wc is needed by jdk-1.6.0_45-fcs.i586
/bin/sh is needed by jdk-1.6.0_45-fcs.i586
sun-javadb-common is needed by sun-javadb-core-10.6.2-1.1.i386
/bin/sh is needed by sun-javadb-core-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-demo-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-docs-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-javadoc-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-client-10.6.2-1.1.i386
为什么我有这种奇怪的依赖性？例如
/bin/ls is needed by jdk-1.6.0_45-fcs.i586
我的系统上肯定有ls命令，为什么 Java 安装会抱怨它？
由于 Java 6 在 Debian 5 中不可用，我决定从 Oracle 那里获取它。我已经在文件 jdk-6u45-linux-i586-rpm.bin 中下载了 Java 6 SDK。但是如何安装呢？
我执行jdk-6u45-linux-i586-rpm.bin并得到了几个文件：
jdk-6u45-linux-i586.rpm
sun-javadb-core-10.6.2-1.1.i386.rpm
sun-javadb-demo-10.6.2-1.1.i386.rpm
sun-javadb-docs-10.6.2-1.1.i386.rpm
sun-javadb-javadoc-10.6.2-1.1.i386.rpm
sun-javadb-client-10.6.2-1.1.i386.rpm
我接下来应该做什么？
UPD
执行后：
rpm -ivh jdk-6u45-linux-i586.rpm sun-javadb-core-10.6.2-1.1.i386.rpm sun-javadb-demo-10.6.2-1.1.i386.rpm sun-javadb-docs-10.6.2-1.1.i386.rpm sun-javadb-javadoc-10.6.2-1.1.i386.rpm sun-javadb-client-10.6.2-1.1.i386.rpm
得到输出：
/bin/basename is needed by jdk-1.6.0_45-fcs.i586
/bin/cat is needed by jdk-1.6.0_45-fcs.i586
/bin/cp is needed by jdk-1.6.0_45-fcs.i586
/bin/gawk is needed by jdk-1.6.0_45-fcs.i586
/bin/grep is needed by jdk-1.6.0_45-fcs.i586
/bin/ln is needed by jdk-1.6.0_45-fcs.i586
/bin/ls is needed by jdk-1.6.0_45-fcs.i586
/bin/mkdir is needed by jdk-1.6.0_45-fcs.i586
/bin/mv is needed by jdk-1.6.0_45-fcs.i586
/bin/pwd is needed by jdk-1.6.0_45-fcs.i586
/bin/rm is needed by jdk-1.6.0_45-fcs.i586
/bin/sed is needed by jdk-1.6.0_45-fcs.i586
/bin/sort is needed by jdk-1.6.0_45-fcs.i586
/bin/touch is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/cut is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/dirname is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/expr is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/find is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/tail is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/tr is needed by jdk-1.6.0_45-fcs.i586
/usr/bin/wc is needed by jdk-1.6.0_45-fcs.i586
/bin/sh is needed by jdk-1.6.0_45-fcs.i586
sun-javadb-common is needed by sun-javadb-core-10.6.2-1.1.i386
/bin/sh is needed by sun-javadb-core-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-demo-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-docs-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-javadoc-10.6.2-1.1.i386
sun-javadb-common is needed by sun-javadb-client-10.6.2-1.1.i386
自从我运行 Old Debian Lenny 以来，我似乎无法安装任何软件。是否有可能以某种方式更改系统的安装源？
更新程序
我已经更新了源，但仍然无法安装软件：
# Line commented out by installer because it failed to verify:
#deb http://security.debian.org/ lenny/updates main contrib
# Line commented out by installer because it failed to verify:
#deb-src http://security.debian.org/ lenny/updates main contribi
deb http://archive.debian.org/debian-archive/debian/ lenny main contrib non-fre
deb http://archive.debian.org/debian-security/ lenny/updates main contrib non-free
我在我的 Centos7 上使用 KDE 桌面。最近我安装了 Gnome。我期待我可以在系统登录时在 KDE/Gnome 之间切换，但我没有任何选择：
现在总是启动 Gnome，如何找回 KDE？
尝试将 git 安装到 32 位 Centos 7：
sudo yum install git
得到答案：
Requires: perl(Error)
如何解决这个问题并安装 git？如果需要，为什么它不尝试下载 perl？
升级版：
我机器上的存储库列表：
尝试在 Raspberry Pi3 中安装 vim-gnome。最后报错：
E: Failed to fetch http://mirrordirector.raspbian.org/raspbian/pool/main/p/perl/libperl5.20_5.20.2-3+deb8u8_armhf.deb: 404 Not Found [IP: 93.93.128.193 80]
如何解决？
整个日志：
sudo aptitude install vim-gnome
The following NEW packages will be installed:
gnome-mime-data libart-2.0-2 libbonobo2-0 libbonobo2-common{a} libbonoboui2-0{a} libbonoboui2-common libgail18 libglade2-0 libgnome-2-0 libgnome2-common libgnomecanvas2-0
libgnomecanvas2-common libgnomeui-0{a} libgnomeui-common libgnomevfs2-0 libgnomevfs2-common libgnomevfs2-extra liblua5.2-0{a} liborbit-2-0{a} libperl5.20{a} vim-gnome vim-gui-common{a}
0 packages upgraded, 22 newly installed, 0 to remove and 1 not upgraded.
Need to get 7,645 kB of archives. After unpacking 32.7 MB will be used.
Do you want to continue? [Y/n/?] y
Get: 1 http://mirrordirector.raspbian.org/raspbian/ jessie/main libart-2.0-2 armhf 2.3.21-2 [63.8 kB]
Get: 2 http://mirrordirector.raspbian.org/raspbian/ jessie/main libbonobo2-common all 2.32.1-3 [243 kB]
Get: 3 http://mirrordirector.raspbian.org/raspbian/ jessie/main liborbit-2-0 armhf 1:2.14.19-0.3 [196 kB]
Get: 4 http://mirrordirector.raspbian.org/raspbian/ jessie/main libbonobo2-0 armhf 2.32.1-3 [236 kB]
Get: 5 http://mirrordirector.raspbian.org/raspbian/ jessie/main libglade2-0 armhf 1:2.6.4-2 [76.2 kB]
Get: 6 http://mirrordirector.raspbian.org/raspbian/ jessie/main gnome-mime-data all 2.18.0-1 [725 kB]
Get: 7 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnomevfs2-common all 1:2.24.4-6 [763 kB]
Get: 8 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnomevfs2-0 armhf 1:2.24.4-6 [450 kB]
Get: 9 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnome2-common all 2.32.1-5 [936 kB]
Err http://mirrordirector.raspbian.org/raspbian/ jessie/main libperl5.20 armhf 5.20.2-3+deb8u8
404 Not Found [IP: 93.93.128.193 80]
Get: 10 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnome-2-0 armhf 2.32.1-5 [463 kB]
Get: 11 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgail18 armhf 2.24.25-3+deb8u2 [537 kB]
Get: 12 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnomecanvas2-common all 2.30.3-2 [132 kB]
Get: 13 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnomecanvas2-0 armhf 2.30.3-2 [94.7 kB]
Get: 14 http://mirrordirector.raspbian.org/raspbian/ jessie/main libbonoboui2-common all 2.24.5-2 [192 kB]
Get: 15 http://mirrordirector.raspbian.org/raspbian/ jessie/main libbonoboui2-0 armhf 2.24.5-2 [177 kB]
Get: 16 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnomeui-common all 2.24.5-3 [514 kB]
Get: 17 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnomeui-0 armhf 2.24.5-3 [285 kB]
Get: 18 http://mirrordirector.raspbian.org/raspbian/ jessie/main liblua5.2-0 armhf 5.2.3-1.1 [64.8 kB]
Get: 19 http://mirrordirector.raspbian.org/raspbian/ jessie/main libgnomevfs2-extra armhf 1:2.24.4-6 [351 kB]
Get: 20 http://mirrordirector.raspbian.org/raspbian/ jessie/main vim-gui-common all 2:7.4.488-7+deb8u3 [150 kB]
Get: 21 http://mirrordirector.raspbian.org/raspbian/ jessie/main vim-gnome armhf 2:7.4.488-7+deb8u3 [993 kB]
Fetched 7,643 kB in 13s (566 kB/s)
Selecting previously unselected package libart-2.0-2:armhf.
(Reading database ... 124424 files and directories currently installed.)
Preparing to unpack .../libart-2.0-2_2.3.21-2_armhf.deb ...
Unpacking libart-2.0-2:armhf (2.3.21-2) ...
Selecting previously unselected package libbonobo2-common.
Preparing to unpack .../libbonobo2-common_2.32.1-3_all.deb ...
Unpacking libbonobo2-common (2.32.1-3) ...
Selecting previously unselected package liborbit-2-0:armhf.
Preparing to unpack .../liborbit-2-0_1%3a2.14.19-0.3_armhf.deb ...
Unpacking liborbit-2-0:armhf (1:2.14.19-0.3) ...
Selecting previously unselected package libbonobo2-0:armhf.
Preparing to unpack .../libbonobo2-0_2.32.1-3_armhf.deb ...
Unpacking libbonobo2-0:armhf (2.32.1-3) ...
Selecting previously unselected package libglade2-0:armhf.
Preparing to unpack .../libglade2-0_1%3a2.6.4-2_armhf.deb ...
Unpacking libglade2-0:armhf (1:2.6.4-2) ...
Selecting previously unselected package gnome-mime-data.
Preparing to unpack .../gnome-mime-data_2.18.0-1_all.deb ...
Unpacking gnome-mime-data (2.18.0-1) ...
Selecting previously unselected package libgnomevfs2-common.
Preparing to unpack .../libgnomevfs2-common_1%3a2.24.4-6_all.deb ...
Unpacking libgnomevfs2-common (1:2.24.4-6) ...
Selecting previously unselected package libgnomevfs2-0:armhf.
Preparing to unpack .../libgnomevfs2-0_1%3a2.24.4-6_armhf.deb ...
Unpacking libgnomevfs2-0:armhf (1:2.24.4-6) ...
Selecting previously unselected package libgnome2-common.
Preparing to unpack .../libgnome2-common_2.32.1-5_all.deb ...
Unpacking libgnome2-common (2.32.1-5) ...
Selecting previously unselected package libgnome-2-0:armhf.
Preparing to unpack .../libgnome-2-0_2.32.1-5_armhf.deb ...
Unpacking libgnome-2-0:armhf (2.32.1-5) ...
Selecting previously unselected package libgail18:armhf.
Preparing to unpack .../libgail18_2.24.25-3+deb8u2_armhf.deb ...
Unpacking libgail18:armhf (2.24.25-3+deb8u2) ...
Selecting previously unselected package libgnomecanvas2-common.
Preparing to unpack .../libgnomecanvas2-common_2.30.3-2_all.deb ...
Unpacking libgnomecanvas2-common (2.30.3-2) ...
Selecting previously unselected package libgnomecanvas2-0:armhf.
Preparing to unpack .../libgnomecanvas2-0_2.30.3-2_armhf.deb ...
Unpacking libgnomecanvas2-0:armhf (2.30.3-2) ...
Selecting previously unselected package libbonoboui2-common.
Preparing to unpack .../libbonoboui2-common_2.24.5-2_all.deb ...
Unpacking libbonoboui2-common (2.24.5-2) ...
Selecting previously unselected package libbonoboui2-0:armhf.
Preparing to unpack .../libbonoboui2-0_2.24.5-2_armhf.deb ...
Unpacking libbonoboui2-0:armhf (2.24.5-2) ...
Selecting previously unselected package libgnomeui-common.
Preparing to unpack .../libgnomeui-common_2.24.5-3_all.deb ...
Unpacking libgnomeui-common (2.24.5-3) ...
Selecting previously unselected package libgnomeui-0:armhf.
Preparing to unpack .../libgnomeui-0_2.24.5-3_armhf.deb ...
Unpacking libgnomeui-0:armhf (2.24.5-3) ...
Selecting previously unselected package liblua5.2-0:armhf.
Preparing to unpack .../liblua5.2-0_5.2.3-1.1_armhf.deb ...
Unpacking liblua5.2-0:armhf (5.2.3-1.1) ...
Selecting previously unselected package libgnomevfs2-extra:armhf.
Preparing to unpack .../libgnomevfs2-extra_1%3a2.24.4-6_armhf.deb ...
Unpacking libgnomevfs2-extra:armhf (1:2.24.4-6) ...
Processing triggers for man-db (2.7.5-1~bpo8+1) ...
Processing triggers for gconf2 (3.2.6-3) ...
Setting up libart-2.0-2:armhf (2.3.21-2) ...
Setting up libbonobo2-common (2.32.1-3) ...
Setting up liborbit-2-0:armhf (1:2.14.19-0.3) ...
Setting up libbonobo2-0:armhf (2.32.1-3) ...
Setting up libglade2-0:armhf (1:2.6.4-2) ...
Setting up gnome-mime-data (2.18.0-1) ...
Setting up libgnomevfs2-common (1:2.24.4-6) ...
Setting up libgnomevfs2-0:armhf (1:2.24.4-6) ...
Setting up libgnome2-common (2.32.1-5) ...
Setting up libgnome-2-0:armhf (2.32.1-5) ...
Setting up libgail18:armhf (2.24.25-3+deb8u2) ...
Setting up libgnomecanvas2-common (2.30.3-2) ...
Setting up libgnomecanvas2-0:armhf (2.30.3-2) ...
Setting up libbonoboui2-common (2.24.5-2) ...
Setting up libbonoboui2-0:armhf (2.24.5-2) ...
Setting up libgnomeui-common (2.24.5-3) ...
Setting up libgnomeui-0:armhf (2.24.5-3) ...
Setting up liblua5.2-0:armhf (5.2.3-1.1) ...
Setting up libgnomevfs2-extra:armhf (1:2.24.4-6) ...
Processing triggers for libc-bin (2.19-18+deb8u10) ...
E: Failed to fetch http://mirrordirector.raspbian.org/raspbian/pool/main/p/perl/libperl5.20_5.20.2-3+deb8u8_armhf.deb: 404 Not Found [IP: 93.93.128.193
尝试在 32 位 CentOS 6.9 中安装 VMware Tools。
我愿意：
yum install open-vm-tools
得到输出：
No package open-vm-tools available.
如何为 CentOS 6.9 安装 VMware Tools？
UPD
我做了：
yum --enablerepo=extras install epel-release
yum install open-vm-tools
安装过程中没有错误。
但是 VMware 工具仍然无法正常工作。没有复制/粘贴功能，没有文件复制到/从主机。
Mashine重启没有帮助。
试图重新启动服务：
/etc/vmware-tools/services.sh restart
但是发现没有这个目录/etc/vmware-tools/。位于哪里vmware-tools？
怎么vmware-tools做作业？