1、按系列罗列 Linux 的发行版，并描述不同发行版之间的联系与区别。
slackware：SUSE Linux Enterprise Server，OpenSuse debian：ubuntu，deepin，mint redhat：RHEL，CentOS，Fedora 本次学习用到的： CentOS is a Linux distribution that provides a free, community-supported computing platform functionally compatible with its upstream source, Red Hat Enterprise Linux. Ubuntu is a Linux distribution based on Debian mostly composed of free and open-source software. Ubuntu is officially released in three editions: Desktop, Server, and Core for Internet of things devices and robots. 学习使用版本： CentOS-8.1.1911-x86_64-dvd1.iso CentOS-7-x86_64-Everything-1908.iso CentOS-6.10-x86_64-bin-DVD1.iso ubuntu-18.04.5-server-amd64.iso
2、安装 Centos7、6 操作系统，创建一个自己名字的用户名，并可以正常登录，将主要步骤截图。
[root@centos7 ~]# useradd zhl [root@centos7 ~]# cat /etc/passwd | grep zhl zhl:x:1001:1001::/home/zhl:/bin/bash [root@centos7 ~]# passwd zhl Changing password for user zhl. New password: Retype new password: passwd: all authentication tokens updated successfully. [root@centos7 ~]# su - zhl Last login: Sun Oct 4 16:03:41 CST 2020 on pts/0 [zhl@centos7 ~]$ id uid=1001(zhl) gid=1001(zhl) groups=1001(zhl) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
[root@centos6 ~]# useradd zhl [root@centos6 ~]# cat /etc/passwd | grep zhl zhl:x:501:501::/home/zhl:/bin/bash [root@centos6 ~]# su zhl [zhl@centos6 root]$ id uid=501(zhl) gid=501(zhl) groups=501(zhl) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
3、配置环境变量，实现执行 history 的时候可以看到执行命令的时间。
[root@centos7 ~]# HISTTIMEFORMAT="%F %T " [root@centos7 ~]# history 28 2020-10-04 16:16:16 HISTTIMEFORMAT="%F %T " 29 2020-10-04 16:16:21 history
4、总结 Linux 哲学思想。
一切都是一个文件（包括硬件） 小型，单一用途的程序 链接程序，共同完成复杂的任务 避免令人困惑的用户界面 配置数据存储在文本中
5、总结 Linux 常用命令使用格式，并用实例说明。例如 echo、screen、date、ifconfig、export 等命令
echo [root@centos8 ~]# help echo echo: echo [-neE] [arg ...] Write arguments to the standard output.
Display the ARGs, separated by a single space character and followed by a
newline, on the standard output.
Options:
-n do not append a newline
-e enable interpretation of the following backslash escapes
-E explicitly suppress interpretation of backslash escapes
[root@centos8 ~]# echo -e 'a\x0Ab' a b
screen [root@centos7 ~]# screen --help Use: screen [-opts] [cmd [args]] or: screen -r [host.tty]
Options: -4 Resolve hostnames only to IPv4 addresses. -6 Resolve hostnames only to IPv6 addresses. -a Force all capabilities into each window's termcap. -A -[r|R] Adapt all windows to the new display width & height. -c file Read configuration file instead of '.screenrc'. -d (-r) Detach the elsewhere running screen (and reattach here). -dmS name Start as daemon: Screen session in detached mode. -D (-r) Detach and logout remote (and reattach here). -D -RR Do whatever is needed to get a screen session. -e xy Change command characters. -f Flow control on, -fn = off, -fa = auto. -h lines Set the size of the scrollback history buffer. -i Interrupt output sooner when flow control is on. -l Login mode on (update /var/run/utmp), -ln = off. -ls [match] or -list Do nothing, just list our SockDir [on possible matches]. -L Turn on output logging. -m ignore $STY variable, do create a new screen session. -O Choose optimal output rather than exact vt100 emulation. -p window Preselect the named window if it exists. -q Quiet startup. Exits with non-zero return code if unsuccessful. -Q Commands will send the response to the stdout of the querying process. -r [session] Reattach to a detached screen process. -R Reattach if possible, otherwise start a new session. -s shell Shell to execute rather than $SHELL. -S sockname Name this session <pid>.sockname instead of <pid>.<tty>.<host>. -t title Set title. (window's name). -T term Use term as $TERM for windows, rather than "screen". -U Tell screen to use UTF-8 encoding. -v Print "Screen version 4.01.00devel (GNU) 2-May-06". -wipe [match] Do nothing, just clean up SockDir [on possible matches]. -x Attach to a not detached screen. (Multi display mode). -X Execute <cmd> as a screen command in the specified session. [root@centos7 ~]# screen -ls There is a screen on: 71922.pts-0.centos7 (Attached) 1 Socket in /var/run/screen/S-root.
date [root@centos8 ~]# date --help Usage: date [OPTION]... [+FORMAT] or: date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]] Display the current time in the given FORMAT, or set the system date.
Mandatory arguments to long options are mandatory for short options too.
-d, --date=STRING display time described by STRING, not 'now'
--debug annotate the parsed date,
and warn about questionable usage to stderr
-f, --file=DATEFILE like --date; once for each line of DATEFILE
-I[FMT], --iso-8601[=FMT] output date/time in ISO 8601 format.
FMT='date' for date only (the default),
'hours', 'minutes', 'seconds', or 'ns'
for date and time to the indicated precision.
Example: 2006-08-14T02:34:56-06:00
-R, --rfc-email output date and time in RFC 5322 format.
Example: Mon, 14 Aug 2006 02:34:56 -0600
--rfc-3339=FMT output date/time in RFC 3339 format.
FMT='date', 'seconds', or 'ns'
for date and time to the indicated precision.
Example: 2006-08-14 02:34:56-06:00
-r, --reference=FILE display the last modification time of FILE
-s, --set=STRING set time described by STRING
-u, --utc, --universal print or set Coordinated Universal Time (UTC)
--help display this help and exit
--version output version information and exit
[root@centos8 ~]# date -d @date +%s
Sun Oct 4 21:10:46 CST 2020
ifconfig [root@centos8 ~]# ifconfig --help Usage: ifconfig [-a] [-v] [-s] <interface> [[<AF>] <address>] [add <address>[/<prefixlen>]] [del <address>[/<prefixlen>]] [[-]broadcast [<address>]] [[-]pointopoint [<address>]] [netmask <address>] [dstaddr <address>] [tunnel <address>] [outfill <NN>] [keepalive <NN>] [hw <HW> <address>] [mtu <NN>] [[-]trailers] [[-]arp] [[-]allmulti] [multicast] [[-]promisc] [mem_start <NN>] [io_addr <NN>] [irq <NN>] [media <type>] [txqueuelen <NN>] [[-]dynamic] [up|down] ... [root@centos8 ~]# ifconfig ens33 ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.0.0.201 netmask 255.255.255.0 broadcast 10.0.0.255 inet6 fe80::b42f:c7f4:8d16:bc0e prefixlen 64 scopeid 0x20<link> ether 00:0c:29:2e:10:39 txqueuelen 1000 (Ethernet) RX packets 26252 bytes 10782373 (10.2 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 9679 bytes 1273609 (1.2 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
export [root@centos8 ~]# help export export: export [-fn] [name[=value] ...] or export -p Set export attribute for shell variables.
Marks each NAME for automatic export to the environment of subsequently
executed commands. If VALUE is supplied, assign VALUE before exporting.
Options:
-f refer to shell functions
-n remove the export property from each NAME
-p display a list of all exported variables and functions
An argument of `--' disables further option processing.
Exit Status:
Returns success unless an invalid option is given or NAME is invalid.
[root@centos8 ~]# export HISTTIMEFORMAT="%F %T " [root@centos8 ~]# echo $HISTTIMEFORMAT %F %T
tips： [root@centos8 ~]# hostname -I 10.0.0.201 192.168.122.1 [root@centos6 ~]# cat /etc/inittab | grep -v "#" id:3:initdefault: [root@centos8 ~]# systemctl get-default multi-user.target [root@centos8 ~]# systemctl set-default multi-user.target [root@centos8 ~]# runlevel N 3
Linux 基础入门 内容概述 1 Linux 基础 1.1 用户类型 1.2 终端 terminal 1.2.1 终端类型 1.2.2 查看当前的终端设备
[root@centos8 ~]# tty /dev/pts/0 etc相当于Windows注册表 登录前的提示 [root@centos8 ~]# cat /etc/issue 登录后的提示 [root@centos8 ~]# cat /etc/motd [root@centos8 ~]# ps aux | grep bash root 858 0.0 0.1 25380 2464 ? S 15:55 0:00 /bin/bash /usr/sbin/ksmtuned root 1616 0.0 0.2 26560 5084 tty1 Ss+ 15:56 0:00 -bash root 1936 0.0 0.2 26824 5548 pts/0 Ss 16:05 0:00 -bash root 4321 0.0 0.0 12108 964 pts/0 R+ 20:09 0:00 grep --color=auto bash
1.3 交互式接口 1.3.1 交互式接口类型 1.3.2 什么是 shell
shell是命令解释器，也是一种高级程序设计语言
1.3.3 各种 shell 1.3.4 bash shell
[root@centos8 ~]# echo $SHELL /bin/bash 显示当前系统使用的所有shell [root@centos8 ~]# cat /etc/shells /bin/sh /bin/bash /usr/bin/sh /usr/bin/bash
1.4 设置主机名
[root@centos8 ~]# hostname centos8.magedu.org wang@ubuntu1804:~$ cat /etc/hostname ubuntu1804 root@ubuntu1804:~# hostname ubuntu1804.magedu.org root@ubuntu1804:~# hostname ubuntu1804.magedu.org root@ubuntu1804:~# hostnamectl set-hostname ubuntu1804.magedu.org root@ubuntu1804:~# cat /etc/hostname ubuntu1804.magedu.org 注意：主机名不要使用下划线
1.5 命令提示符
[root@centos8 ~]# echo $PS1 [\u@\h \W]$ 个人设置 [root@centos8 ~]# cat /etc/profile.d/env.sh
1.6 执行命令 1.6.1 执行命令过程 1.6.2 shell 中可执行的两类命令
特殊外部命令，别名（磁盘上的文件，不属于bash内部） [root@centos8 ~]# ls /bin/bash /bin/bash [root@centos8 ~]# ll /bin/bash -rwxr-xr-x. 1 root root 1219248 Nov 9 2019 /bin/bash [root@centos8 bin]# ls /bin/ls /bin/ls [root@centos8 bin]# ll /bin/ls -rwxr-xr-x. 1 root root 166448 May 12 2019 /bin/ls [root@centos8 bin]# type hostname hostname is hashed (/usr/bin/hostname)（第一次执行在磁盘中找，第二次执行时文件路径已存在hash内存中） [root@centos8 bin]# type echo echo is a shell builtin [root@centos8 ~]# echo $PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin [root@centos8 ~]# hash hits command 2 /usr/bin/hostname 4 /usr/bin/ls(执行了四次了) [root@centos8 ~]# type type type is a shell builtin
shell不同，内部命令不同，所以会有同名的内部、外部命令 [root@centos8 ~]# type -a echo echo is a shell builtin echo is /usr/bin/echo
1.6.2.1 内部命令相关
enable . 对等 enable source 修改完配置文件后，不用重启、退出重登，应用下 #. /etc/profile.d/env.sh #source /etc/profile.d/env.sh yum install nano dnf install nano(centos8) [root@centos8 ~]# help [root@centos8 ~]# enable enable可以禁用内部命令 -n（比如禁用内部echo） enable输出中就没了被禁用命令，help会标记被禁用 此时外部echo还能用 enable -n enable，由于没保存文件，exit，再登录，就正常了
1.6.2.2 执行外部命令
退出后，hash缓存会清除 hash -r清除hash缓存 避免命令被移走，而之前hash存放之前的路径缓存，执行时报没有命令 hash -d hostanme清理单条hash缓存 [root@centos8 ~]# type -a echo echo is a shell builtin echo is /usr/bin/echo [root@centos8 ~]# which enable /usr/bin/which: no enable in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin) [root@centos8 ~]# which reboot /usr/sbin/reboot [root@centos8 ~]# which echo /usr/bin/echo [root@centos8 ~]# whereis ls ls: /usr/bin/ls /usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz（多显示了帮助）
1.6.3 命令别名
每个用户都有.bashrc，在这里加别名 [root@centos8 ~]# cat .bashrc | grep alias # User specific aliases and functions alias rm='rm -i' alias cp='cp -i' alias mv='mv -i' [root@centos8 ~]# 修改完 #. .bashrc #source .bashrc unalias [root@centos8 ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 200G 0 disk ├─sda1 8:1 0 1G 0 part /boot ├─sda2 8:2 0 100G 0 part / ├─sda3 8:3 0 50G 0 part /data ├─sda4 8:4 0 1K 0 part └─sda5 8:5 0 4G 0 part [SWAP] sr0 11:0 1 7G 0 rom(光盘) 添加硬盘 不用重启，扫盘 [root@centos8 ~]# type ls ls is aliased to `ls --color=auto' [root@centos8 ~]# which ls alias ls='ls --color=auto' /usr/bin/ls [root@centos8 ~]# ls [root@centos8 ~]# type cdnetwork（判断是否已有命令名） -bash: type: cdnetwork: not found [root@centos8 ~]# alias cdnetwork="cd /etc/sysconfig/network-scripts/" [root@centos8 ~]# type cdnetwork（此时可以看出已经是别名） exit，别名消失 非要把别名设置成已有命令 别名优先级高 别名>内部命令>外部命令（hash）>无此命令 hash缓存的外部命令 找外部命令，先hash，后路径
1.6.4 命令格式
[root@centos8 ~]# free -h total used free shared buff/cache available Mem: 1.9Gi 298Mi 1.3Gi 9.0Mi 326Mi 1.5Gi Swap: 4.0Gi 0B 4.0Gi [root@centos8 ~]# free --human total used free shared buff/cache available Mem: 1.9Gi 298Mi 1.3Gi 9.0Mi 326Mi 1.5Gi Swap: 4.0Gi 0B 4.0Gi [root@centos8 ~]# ls -a . .bash_logout .config Documents initial-setup-ks.cfg .pki Videos .. .bash_profile .cshrc Downloads .local Public .Xauthority anaconda-ks.cfg .bashrc .dbus .esd_auth Music .tcshrc .bash_history .cache Desktop .ICEauthority Pictures Templates [root@centos8 ~]# ls --all . .bash_logout .config Documents initial-setup-ks.cfg .pki Videos .. .bash_profile .cshrc Downloads .local Public .Xauthority anaconda-ks.cfg .bashrc .dbus .esd_auth Music .tcshrc .bash_history .cache Desktop .ICEauthority Pictures Templates [root@centos8 ~]# ps PID TTY TIME CMD 6567 pts/1 00:00:00 bash 7889 pts/1 00:00:00 ps [root@centos8 ~]# ps a PID TTY STAT TIME COMMAND 1616 tty1 Ss+ 0:00 -bash 6567 pts/1 Ss 0:00 -bash 7890 pts/1 R+ 0:00 ps a [root@centos8 ~]# ps au USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1616 0.0 0.2 26560 5084 tty1 Ss+ 00:45 0:00 -bash root 6567 0.0 0.2 26692 5464 pts/1 Ss 08:52 0:00 -bash root 7891 0.0 0.1 57184 3800 pts/1 R+ 11:00 0:00 ps au [root@centos8 ~]# iptables -vnL Chain INPUT (policy ACCEPT 5932 packets, 8898K bytes) pkts bytes target prot opt in out source destination 0 0 ACCEPT udp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 udp dpt:53 0 0 ACCEPT tcp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:53 0 0 ACCEPT udp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 udp dpt:67 0 0 ACCEPT tcp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:67
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- * virbr0 0.0.0.0/0 192.168.122.0/24 ctstate RELATED,ESTABLISHED 0 0 ACCEPT all -- virbr0 * 192.168.122.0/24 0.0.0.0/0 0 0 ACCEPT all -- virbr0 virbr0 0.0.0.0/0 0.0.0.0/0 0 0 REJECT all -- * virbr0 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable 0 0 REJECT all -- virbr0 * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable
Chain OUTPUT (policy ACCEPT 3290 packets, 343K bytes) pkts bytes target prot opt in out source destination 0 0 ACCEPT udp -- * virbr0 0.0.0.0/0 0.0.0.0/0 udp dpt:68 [root@centos8 ~]# iptables -Lnv iptables: No chain/target/match by that name. ^C强行退出 ^D正常退出
1.7 常见命令 1.7.1 查看硬件信息 1.7.1.1 查看 CPU
[root@centos8 ~]# lscpu [root@centos8 ~]# cat /proc/cpuinfo
1.7.1.2 查看内存大小
[root@centos8 ~]# free total used free shared buff/cache available Mem: 2012252 306036 1371512 9368 334704 1540244 Swap: 4194300 0 4194300 [root@centos8 ~]# cat /proc/meminfo proc显示的是内存中的文件 [root@centos8 ~]# ll /proc/meminfo -r--r--r--. 1 root root 0 Oct 2 15:54 /proc/meminfo（大小为0）
1.7.1.3 查看硬盘和分区情况
[root@centos8 ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 200G 0 disk ├─sda1 8:1 0 1G 0 part /boot ├─sda2 8:2 0 100G 0 part / ├─sda3 8:3 0 50G 0 part /data ├─sda4 8:4 0 1K 0 part └─sda5 8:5 0 4G 0 part [SWAP] sr0 11:0 1 7G 0 rom [root@centos8 ~]# cat /proc/partitions major minor #blocks name
11 0 7377920 sr0 8 0 209715200 sda 8 1 1048576 sda1 8 2 104857600 sda2 8 3 52428800 sda3 8 4 1 sda4 8 5 4194304 sda5
1.7.2 查看系统版本信息 1.7.2.1 查看内核版本
[root@centos8 ~]# uname -r 4.18.0-147.el8.x86_64
1.7.2.2 查看操作系统发行版本
[root@centos8 ~]# cat /etc/redhat-release CentOS Linux release 8.1.1911 (Core) [root@centos8 ~]# cat /etc/os-release
1.7.3 日期和时间
[root@centos8 ~]# date（修改时间，也是保存在内存中，重启时间又恢复） 硬件时间，主板时间 [root@centos8 ~]# clock 2020-10-03 11:54:04.446048+08:00 [root@centos8 ~]# clock -s（以硬件时间矫正系统时间） [root@centos8 ~]# ll /etc/localtime lrwxrwxrwx. 1 root root 35 Oct 1 19:46 /etc/localtime -> ../usr/share/zoneinfo/Asia/Shanghai [root@centos8 ~]# timedatectl set-timezone Asia/Shanghai Ubuntu # cat /etc/timezone
1.7.4 关机和重启
root@ubuntu1804:~# reboot root@ubuntu1804:~# init 6 root@ubuntu1804:~# init 0
1.7.5 用户登录信息查看命令
[root@centos8 ~]# w 13:55:51 up 13:11, 2 users, load average: 0.00, 0.00, 0.00 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT root tty1 - Fri15 21:59m 0.23s 0.23s -bash root pts/1 10.0.0.1 08:52 0.00s 0.21s 0.01s w
1.7.6 文本编辑 1.7.7 会话管理
关闭窗口，会话结束，会话内部的进程也会随之终止，不管有没有运行完
1.7.7.1 screen 1.7.7.2 tmux 1.7.8 输出信息 echo
echo 输出的字符串间以空白字符隔开，并在最后加上换行号 -n 不自动换行 [root@centos8 ~]# echo -e 'a\x0Ab' a b
1.8 字符集和编码
字符集（字是如何写） 字符与二进制对应关系 ASCII码 编码（在磁盘上的保存形式） 字体，表现形式
1.8.1 ASCII 码 1.8.2 Unicode
[root@centos8 ~]# echo $LANG en_US.UTF-8 [root@centos8 ~]# cat /tmp/test.txt abc [root@centos8 ~]# hexdump -C /tmp/test.txt 00000000 61 62 63 20 0a |abc .| 00000005 [root@centos8 ~]# ll /tmp/test.txt -rw-r--r--. 1 root root 5 Oct 3 16:01 /tmp/test.txt [root@centos8 ~]# man ascii
1.9 命令行扩展和被括起来的集合 1.9.1 命令行扩展：`` 和 $ ()
[root@centos8 ~]# touch date +%F.txt
[root@centos8 ~]# touch $(date +%F).txt
[root@centos8 ~]# ls $(echo $(date +F%).txt)
[root@centos8 ~]# ls echo $(date +F%).txt
[root@centos8 ~]# ls $(echo date +F%.txt)
单引号：六亲不认 反向单引号：变量和命令都识别 双引号：不能识别命令
1.9.2 括号扩展：{}
[root@centos8 ~]# echo {1,3,5}
1 3 5
[root@centos8 ~]# echo 1 3 5
1 3 5
[root@centos8 ~]# echo user{1,3,5}
user1 user3 user5
[root@centos8 ~]# echo file{1,3,5}.txt
file1.txt file3.txt file5.txt
[root@centos8 ~]# echo {1..10}
1 2 3 4 5 6 7 8 9 10
[root@centos8 ~]# echo {20..10}
20 19 18 17 16 15 14 13 12 11 10
[root@centos8 ~]# echo {20..10..2}
20 18 16 14 12 10
[root@centos8 ~]# echo {a..z}
a b c d e f g h i j k l m n o p q r s t u v w x y z
[root@centos8 ~]# echo {a..z..2}
a c e g i k m o q s u w y
[root@centos8 ~]# echo {000..20..2}
000 002 004 006 008 010 012 014 016 018 020
[root@centos8 ~]# echo {a..Z}
a _ ^ ] [ Z [root@centos8 ~]# man ascii [root@centos8 ~]# echo {A..z} A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ ] ^ _ a b c d e f g h i j k l m n o p q r s t u v w x y z
[root@centos8 ~]# echo file{1..10}.{txt,log}
file1.txt file1.log file2.txt file2.log file3.txt file3.log file4.txt file4.log file5.txt file5.log file6.txt file6.log file7.txt file7.log file8.txt file8.log file9.txt file9.log file10.txt file10.log
1.10 tab 键补全 1.10.1 命令补全
命令嵌套子命令（tab子命令补全） [root@centos8 ~]# nmcli connection add delete edit help load monitor show clone down export import modify reload up 需要包 [root@centos8 ~]# rpm -qa bash* bash-completion-2.7-5.el8.noarch
1.10.2 路径补全 1.10.3 双击 Tab 键 1.11 命令行历史
正常退出，历史命令会追加到文件中。登录，会导入内存 [root@centos8 ~]# cat ~/.bash_history [root@centos8 ~]# echo $HISTSIZE 1000 [root@centos8 ~]# cat /etc/profile | grep HISTSIZ HISTSIZE=1000 export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL 改完后 [root@centos8 ~]# source /etc/profile [root@centos8 ~]# history -s rm -rf / [root@centos8 ~]# history 149 echo $HISTSIZE 150 cat /etc/profile | grep HISTSIZ 151 history -s 152 history 153 rm -rf / 154 history [root@centos8 ~]# cat .bash_profile # .bash_profile
# Get the aliases and functions if [ -f ~/.bashrc ]; then . ~/.bashrc fi
# User specific environment and startup programs
PATH=$PATH:$HOME/bin
export PATH
1.12 调用命令行历史 1.13 bash 的快捷键 2 获得帮助 2.1 whatis
[root@centos8 ~]# whatis hostname hostname: nothing appropriate. [root@centos8 ~]# mandb [root@centos8 ~]# whatis hostname hostname (7) - hostname resolution description hostname (1) - show or set the system's host name hostname (5) - Local hostname configuration file [root@centos8 ~]# man -f hostname hostname (7) - hostname resolution description hostname (1) - show or set the system's host name hostname (5) - Local hostname configuration file
2.2 查看命令的帮助
内部命令（type） help man
2.3 --help 或 -h 选项
外部命令
cmd --help
[root@centos8 ~]# date +"%F %T"
2020-10-04 09:58:46
[root@centos8 ~]# touch date +%F_%H-%M-%S.log
[root@centos8 ~]# mv app.log appdate -d '-1 day' +%F.log
2.4 man 命令
[root@centos8 ~]# whereis passwd passwd: /usr/bin/passwd /etc/passwd /usr/share/man/man1/passwd.1.gz /usr/share/man/man5/passwd.5.gz [root@centos8 ~]# whatis passwd openssl-passwd (1ssl) - compute password hashes passwd (1) - update user's authentication tokens passwd (5) - password file [root@centos8 ~]# man 5 passwd [root@centos8 ~]# man -k password [root@centos8 ~]# man 7 utf8 [root@centos8 ~]# man -w ls /usr/share/man/man1/ls.1.gz
2.5 info
[root@centos8 ~]# info ls
2.6 Linux 安装提供的本地文档获取帮助 2.7 命令自身提供的官方使用指南
[root@centos8 doc]# pwd /usr/share/doc
2.8 系统及第三方应用官方文档 2.8.1 通过在线文档获取帮助 2.8.2 Linux 官方在线文档和知识库 2.8.3 红帽全球技术支持服务 2.9 网站和搜索
已学： alias bc cal cat /ect/motd /etc/issue cd clear clock date dnf echo $PS1 $SHELL enable exit file free gedit 图形化 halt hash help hexdump hostname hostnamectl init 0 3 5 6 logout lsblk lscpu man mv nano /etc/motd poweroff ps aux reboot runlevel shutdown sleep sreen sudo -i tmux tty type unalias uptime whereis which whoami who who am i yum
