Linux(1)简单shell命令
与时间相关的shell命令
1、date命令：查看或修改系统时间
例：查看系统时间
[root@localhost profile.d]# date
2019年 09月 17日 星期二 11:20:28 CST
修改系统时间：date 月日时分/date 年月日时分
[root@localhost profile.d]# date 09171121
2019年 09月 17日 星期二 11:21:00 CST
2、cal命令：显示日历
[root@localhost profile.d]# cal
九月 2019
日 一 二 三 四 五 六
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30
3、pwd命令：显示当前目录的绝对路径
[root@localhost profile.d]# pwd
/etc/profile.d
4、cd命令：切换到指定目录
[root@localhost profile.d]# cd /etc
[root@localhost etc]# pwd
/etc
5、ls命令：显示指定目录中的文件和子目录信息
参数 :
- -a 显示所有文件及目录 ，包括隐藏文件和隐藏子目录(ls内定将文件名或目录名称开头为"."的视为隐藏档，不会列出)
- -l 除文件名称外，亦将文件型态、权限、拥有者、文件大小等资讯详细列出
- -r 将文件以相反次序显示(原定依英文字母次序)
- -t 将文件依建立时间之先后次序列出
- -A 同 -a ，但不列出 “.” (目前目录) 及 “…” (父目录)
- -F 在列出的文件名称后加一符号；例如可执行档则加 “*”, 目录则加 “/”
- -R 若目录下有文件，则以下之文件亦皆依序列出
查看当前目录中的文件和子目录
[root@localhost etc]# ls
abrt hosts.allow prelink.conf.d
adjtime hosts.deny printcap
hosts ppp
[root@localhost etc]# ls -a
hba.conf portreserve yum.conf
host.conf postfix yum.repos.d
hostname ppp
hosts prelink.conf.d
查看当前目录中所有文件和子目录的详细信息
[root@localhost etc]# ls -al
总用量 1664
drwxr-xr-x. 159 root root 8192 9月 17 10:25 .
dr-xr-xr-x. 17 root root 4096 9月 8 22:04 ..
drwxr-xr-x. 3 root root 97 9月 8 21:57 abrt
-rw-r--r--. 1 root root 16 9月 8 22:04 adjtime
-rw-r--r--. 1 root root 813 9月 11 2015 yum.conf
drwxr-xr-x. 2 root root 24 9月 8 22:03 yum.repos.d
6、cat命令：显示文本文件的内容
显示/etc/profile目录下的文本文件的内容
[root@localhost etc]# cat /etc/profile
# /etc/profile
# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc
# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.
pathmunge () {
case ":${PATH}:" in
*:"$1":*)
;;
*)
if [ "$2" = "after" ] ; then
PATH=$PATH:$1
else
PATH=$1:$PATH
fi
fi
fi
done
unset i
unset -f pathmunge
文件退出直接输：q
查看当前目录中profile文件的内容，并在每一行前加上行号
[root@localhost etc]# cat -n profile
1 # /etc/profile
2
3 # System wide environment and startup programs, for login setup
4 # Functions and aliases go in /etc/bashrc
5
6 # It's NOT a good idea to change this file unless you know what you
7 # are doing. It's much better to create a custom.sh shell script in
8 # /etc/profile.d/ to make custom changes to your environment, as this
9 # will prevent the need for merging in future updates.
10
11 pathmunge () {
12 case ":${PATH}:" in
13 *:"$1":*)
14 ;;
15 *)
16 if [ "$2" = "after" ] ; then
17 PATH=$PATH:$1
18 else
19 PATH=$1:$PATH
20 fi
21 esac
22 }
23
7、more命令：分屏显示文件的内容
格式：more 文件
[root@localhost etc]# more /etc/profile
# /etc/profile
# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc
# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.
pathmunge () {
case ":${PATH}:" in
*:"$1":*)
;;
*)
if [ "$2" = "after" ] ; then
PATH=$PATH:$1
else
PATH=$1:$PATH
fi
esac
}
less命令与more命令类似
[root@localhost etc]# less /etc/profile
8、tail命令：显示文本文件的结尾部分
[root@localhost etc]# tail /etc/profile
if [ "${-#*i}" != "$-" ]; then
. "$i"
else
. "$i" >/dev/null
fi
fi
done
unset i
unset -f pathmunge
head命令显示文本文件的开头部分
[root@localhost etc]# head -10 /etc/profile
-10是显示前10行
# /etc/profile
# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc
# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.
9、man命令：显式指定命令的手册页帮助信息
[root@localhost etc]# man
您需要什么手册页？
按q键则退出man命令
[root@localhost etc]# man ls
[root@localhost etc]# ls -help
ls：无效选项 -- e
Try 'ls --help' for more information.
[root@localhost etc]# ls --help
用法：ls [选项]... [文件]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all 不隐藏任何以. 开始的项目
-A, --almost-all 列出除. 及.. 以外的任何项目
--author 与-l 同时使用时列出每个文件的作者
-b, --escape 以八进制溢出序列表示不可打印的字符
--block-size=SIZE scale sizes by SIZE before printing them; e.g.,
'--block-size=M' prints sizes in units of
1,048,576 bytes; see SIZE format below
-B, --ignore-backups do not list implied entries ending with ~
清屏
1、clear命令：清除当前终端的屏幕内容
[root@localhost etc]#clean
2、wc命令：显示文本文件的行数、字数、字符数
[root@localhost etc]# wc -c /etc/profile
-c仅显示文件的字节数
1750 /etc/profile
[root@localhost etc]# wc -l /etc/profile
-l仅显示文件的行数
76 /etc/profile
[root@localhost etc]# wc -w /etc/profile
-w仅显示文件的单词数
252 /etc/profile
