一. 文件和目录类
1.1 File exist 文件已经存在
[root@oldboyedu59 ~]# mkdir /data /lidao
[root@oldboyedu59 ~]# mkdir /data /lidao
mkdir: cannot create directory ‘/data’: File exists
mkdir: cannot create directory ‘/lidao’: File existsmkdir: cannot create directory ‘/lidao’: File exists
无法 创建 目录 因为这个目录已经存在
1.2 No such file or directory 没有这个文件或目录（这个东西不存在）
没有这个目录:文件或路径书写错误
[root@oldboyedu59 ~]# mkdir /oldboy
[root@oldboyedu59 ~]# cd oldboy
-bash: cd: oldboy: No such file or directorymkdir命令本身问题:mkdir 命令默认只能创建1层目录 创建多层报错
-p解决
[root@oldboyedu59 ~]# mkdir /data/oldboy/lidao/
mkdir: cannot create directory ‘/data/oldboy/lidao/’: No such file or directorytouch命令只能创建文件,目录不存在则会报错
解决:先创建目录,再创建文件
[root@oldboyedu59 ~]# ls /oldboy/
oldboy.txt
[root@oldboyedu59 ~]# touch /oldboy/lidao/alex/oldboy.txt
touch: cannot touch ‘/oldboy/lidao/alex/oldboy.txt’: No such file or directory排错思路：
1、ls命令检查对应的目录是否存在?
2、目录不存在 先创建目录在创建文件/
1.3 command not found 命令找不到（没有这个命令）
[root@oldboyedu59 ~]# mkdiy
-bash: mkdiy: command not found1.书写错误
2.没有安装
1.4 invalid option 无效的参数（不可用的参数）
[root@oldboyedu59 ~]# touch -p /oldboy/oldboy.txt
touch: invalid option -- 'p'
Try 'touch --help' for more information.1.5 overwrite 覆盖
cp复制如果已经存在这个文件会提示是否覆盖
[root@oldboyedu59 ~]# cp /oldboy/oldboy.txt /tmp/
cp: overwrite ‘/tmp/oldboy.txt’? 1.6 remove regular empty file 是否删除普通文件（空的）
[root@oldboyedu59 ~]# rm /oldboy/oldboy.txt
rm: remove regular empty file ‘/oldboy/oldboy.txt’?1.7 is a directory xxx是一个目录
rm默认无法删除目录
解决:加上-r 或-rf
[root@oldboyedu59 ~]# rm /data/
rm: cannot remove ‘/data/’: Is a directoryvi命令中 使用vi编辑目录也会报错
"/oldboy"
E502: "/oldboy" is a directory
Press ENTER or type command to continue1.8 descend into directory 是否进入目录
[root@oldboyedu59 ~]# rm -r /data/
rm: descend into directory ‘/data/’? y
rm: remove regular empty file ‘/data/oldboy01.txt’? n
rm: remove regular empty file ‘/data/oldboy02.txt’? n
rm: remove regular empty file ‘/data/oldboy03.txt’? n
rm: remove regular empty file ‘/data/oldboy04.txt’? n
rm: remove regular empty file ‘/data/oldboy05.txt’? n
rm: remove regular empty file ‘/data/oldboy06.txt’? n
rm: remove regular empty file ‘/data/oldboy07.txt’? n
rm: remove regular empty file ‘/data/oldboy08.txt’? n
rm: remove regular empty file ‘/data/oldboy09.txt’? n
rm: remove regular empty file ‘/data/oldboy10.txt’? n
rm: remove directory ‘/data/’? n
1.9 Invalid level 无效的层数,层数必须大于0注意参数位置
[root@oldboyedu59 ~]# tree -L -F 2 /
tree: Invalid level, must be greater than 0.1.10 Can't open file for writing 无法打开这个文件
vi中 如果目录不存在就会提示
"/oldbyo/oldboy.txt"
"/oldbyo/oldboy.txt" E212: Can't open file for writing
Press ENTER or type command to continue1.11 No write since last change
E37: No write since last change (add ! to override)
粘包赖(你修改了内容就无法使用:q退出 需要使用:q! 1.12 xx column window is too narrow 窗口只有xx列太窄了 无法完全显示
这是w的坑 空间太小施展不开.
[root@oldboyedu60-lnb ~]# w
w: 39 column window is too narrow二. 网络连接类
2.1 远程连接错误 Connection Failed 连接失败
使用Xshell远程连接失败提示,检查端口是否开启或正确
[c:\~]$
Connecting to 10.0.0.200:233...
Could not connect to '10.0.0.200' (port 233): Connection failed.
Type `help' to learn how to use Xshell prompt.使用telnet测试端口是否打开
[c:\~]$ telnet 10.0.0.200 233
Connecting to 10.0.0.200:233...
Could not connect to '10.0.0.200' (port 233): Connection failed. #233端口没有开启
Type `help' to learn how to use Xshell prompt.端口开启
[c:\~]$ telnet 10.0.0.200 22
Connecting to 10.0.0.200:22...
Connection established. #端口开启
To escape to local shell, press 'Ctrl+Alt+]'.
SSH-2.0-OpenSSH_7.4
Protocol mismatch.
Connection closed by foreign host.
Disconnected from remote host(10.0.0.200:22) at 12:22:54.
Type `help' to learn how to use Xshell prompt.
[c:\~]$ 2.2 yum安装软件故障提示 Could not resolve host无法解析主机
Could not resolve host无法解析主机
主要是系统能否上网和DNS问题.
http://mirrors.tuna.tsinghua.edu.cn/centos/7.6.1810/updates/x86_64/repodata/repomd.xml: [Errno 14] curl#6 -
"Could not resolve host: mirrors.tuna.tsinghua.edu.cn; Unknown error"
Trying other mirror. 2.3 yum安装软件提示:Nothing to do (没事做)
有两种情况:
情况1:软件已经安装并且最新如下:
Package tree-1.6.0-10.el7.x86_64 already installed and latest version
tree软件包已经安装并且是最新版本
Package 2:vim-enhanced-7.4.160-5.el7.x86_64 already installed and latest version
Package 1:bash-completion-2.1-6.el7.noarch already installed and latest version
Nothing to do情况2:软件名字写错或没有配置yum源导致找不到这个软件包
[root@oldboyedu60-lnb ~]# yum install treea -y
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirror.lzu.edu.cn
* extras: mirrors.nwsuaf.edu.cn
* updates: mirrors.nwsuaf.edu.cn
base | 3.6 kB 00:00:00
extras | 3.4 kB 00:00:00
updates | 3.4 kB 00:00:00
No package treea available.
#没有找到叫treea的软件包
Error: Nothing to do2.4 Name or service not known 域名无法识别（无法上网）
原因：
1：DNS配置错误原因
2：Linux无法上网原因
[root@oldboyedu59 ~]# ping baidu.com
ping: baidu.com: Name or service not known
域名无法识别（无法将域名---->ip地址)三. 修改系统基础配置类
3.1 重启网卡报错 device not present
[root@oldboyusd ~]# systemctl restart network
Job for network.service failed because the control process exited with error code.
See "systemctl status network.service" and "journalctl -xe" for details.查看详细错误原因
·journalctl -xe·
Apr 01 15:31:05 oldboyusd.1 network[7816]: Bringing up interface etho: ERROR : [/etc/sysconfig/network-scripts/ifup-eth] Device does not seem to be present, delaying initialization.
Apr 01 15:31:05 oldboyusd.1 /etc/sysconfig/network-scripts/ifup-eth[8019]: Device does not seem to be present, delaying initializatio3.2 修改主机名过程中,命令行中主机名没有变化
1 hostname命令修改主机名（临时 重启服务器之后失效）
[root@oldboyedu59 ~]# hostname
oldboyedu59
[root@oldboyedu59 ~]# hostname oldboyedu59-lnb 2 修改文件内容（写合同 永久 重启服务器之后生效）
vim /etc/hostname
oldboyedu59-lnb3 检查
[root@oldboyedu59 ~]# hostname
oldboyedu59-lnb
[root@oldboyedu59 ~]# cat /etc/hostname
oldboyedu59-lnb命令行中的主机名部分没有改变？
解决：重新登录下即可（断开连接，重新连接）
[root@oldboyedu59-lnb ~]#