《鸟叔私房菜》学习笔记----第五章

1. su - 切换root身份
2. ls -al 查看所有文件详细的权限和指令

root@shun-Inspiron-7472:~# ls -al
总用量 40
drwx------  7 root root 4096 12月  5 19:15 .
drwxr-xr-x 23 root root 4096 12月  5 19:23 ..
-rw-------  1 root root  104 12月  5 19:15 .bash_history
-rw-r--r--  1 root root 3106 8月   7 06:35 .bashrc
drwx------  4 root root 4096 12月  5 19:13 .cache
drwx------  6 root root 4096 12月  5 19:13 .config
drwx------  3 root root 4096 12月  5 19:13 .dbus
drwx------  2 root root 4096 12月  5 19:13 .gvfs
drwxr-xr-x  3 root root 4096 12月  5 19:13 .local
-rw-r--r--  1 root root  148 8月   7 06:35 .profile
root@shun-Inspiron-7472:~# 

第一栏：

第五栏：默认单位为bytes

3. ls --help 或man ls 或info ls 查询ls的详细用法

List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.

必选参数对长短选项同时适用。
  -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 ~
  -c                         with -lt: sort by, and show, ctime (time of last
                               modification of file status information);
                               with -l: show ctime and sort by name;
                               otherwise: sort by ctime, newest first
  -C                         list entries by columns
      --color[=WHEN]         colorize the output; WHEN can be 'always' (default
                               if omitted), 'auto', or 'never'; more info below
  -d, --directory            list directories themselves, not their contents
  -D, --dired                generate output designed for Emacs' dired mode
  -f                         do not sort, enable -aU, disable -ls --color
  -F, --classify             append indicator (one of */=>@|) to entries
      --file-type            likewise, except do not append '*'
      --format=WORD          across -x, commas -m, horizontal -x, long -l,
                               single-column -1, verbose -l, vertical -C
      --full-time            like -l --time-style=full-iso
  -g				类似-l，但不列出所有者
      --group-directories-first
                             group directories before files;
                               can be augmented with a --sort option, but any
                               use of --sort=none (-U) disables grouping
  -G, --no-group             in a long listing, don't print group names
  -h, --human-readable       with -l and/or -s, print human readable sizes
                               (e.g., 1K 234M 2G)
      --si                   likewise, but use powers of 1000 not 1024
  -H, --dereference-command-line
                             follow symbolic links listed on the command line
      --dereference-command-line-symlink-to-dir
                             follow each command line symbolic link
                               that points to a directory
      --hide=PATTERN         do not list implied entries matching shell PATTERN
                               (overridden by -a or -A)
      --hyperlink[=WHEN]     hyperlink file names; WHEN can be 'always'
                               (default if omitted), 'auto', or 'never'
      --indicator-style=WORD  append indicator with style WORD to entry names:
                               none (default), slash (-p),
                               file-type (--file-type), classify (-F)
  -i, --inode                print the index number of each file
  -I, --ignore=PATTERN       do not list implied entries matching shell PATTERN
  -k, --kibibytes            default to 1024-byte blocks for disk usage
  -l				使用较长格式列出信息
  -L, --dereference		当显示符号链接的文件信息时，显示符号链接所指示
				的对象而并非符号链接本身的信息
  -m				所有项目以逗号分隔，并填满整行行宽
  -n, --numeric-uid-gid      like -l, but list numeric user and group IDs
  -N, --literal              print entry names without quoting
  -o                         like -l, but do not list group information
  -p, --indicator-style=slash
                             append / indicator to directories
  -q, --hide-control-chars   print ? instead of nongraphic characters
      --show-control-chars   show nongraphic characters as-is (the default,
                               unless program is 'ls' and output is a terminal)
  -Q, --quote-name           enclose entry names in double quotes
      --quoting-style=WORD   use quoting style WORD for entry names:
                               literal, locale, shell, shell-always,
                               shell-escape, shell-escape-always, c, escape
  -r, --reverse			逆序排列
  -R, --recursive		递归显示子目录
  -s, --size			以块数形式显示每个文件分配的尺寸
  -S                         sort by file size, largest first
      --sort=WORD            sort by WORD instead of name: none (-U), size (-S),
                               time (-t), version (-v), extension (-X)
      --time=WORD            with -l, show time as WORD instead of default
                               modification time: atime or access or use (-u);
                               ctime or status (-c); also use specified time
                               as sort key if --sort=time (newest first)
      --time-style=STYLE     with -l, show times using style STYLE:
                               full-iso, long-iso, iso, locale, or +FORMAT;
                               FORMAT is interpreted like in 'date'; if FORMAT
                               is FORMAT1FORMAT2, then FORMAT1 applies
                               to non-recent files and FORMAT2 to recent files;
                               if STYLE is prefixed with 'posix-', STYLE
                               takes effect only outside the POSIX locale
  -t                         sort by modification time, newest first
  -T, --tabsize=COLS         assume tab stops at each COLS instead of 8
  -u                         with -lt: sort by, and show, access time;
                               with -l: show access time and sort by name;
                               otherwise: sort by access time, newest first
  -U                         do not sort; list entries in directory order
  -v                         natural sort of (version) numbers within text
  -w, --width=COLS           set output width to COLS.  0 means no limit
  -x                         list entries by lines instead of by columns
  -X                         sort alphabetically by entry extension
  -Z, --context              print any security context of each file
  -1                         list one file per line.  Avoid '\n' with -q or -b
      --help		显示此帮助信息并退出
      --version		显示版本信息并退出

The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).

使用色彩来区分文件类型的功能已被禁用，默认设置和 --color=never 同时禁用了它。
使用 --color=auto 选项，ls 只在标准输出被连至终端时才生成颜色代码。
LS_COLORS 环境变量可改变此设置，可使用 dircolors 命令来设置。

退出状态：
 0  正常
 1  一般问题 (例如：无法访问子文件夹)
 2  严重问题 (例如：无法使用命令行参数)

GNU coreutils online help: 
请向 报告ls 的翻译错误
Full documentation at: 
or available locally via: info '(coreutils) ls invocation'
root@shun-Inspiron-7472:~# 

4. 改变文件属性

• chgrp :改变文件所属群组
• chown :改变文件拥有者
• chmod :改变文件的权限, SUID, SGID, SBIT等等的特性

5. 创建空的目录和文件

[root@study ~]# cd /tmp <==切换工作目录到/tmp
[root@study tmp]# mkdir testing <==创建新目录
[root@study tmp]# chmod 744 testing <==变更权限
[root@study tmp]# touch testing/testing <==创建空的文件
[root@study tmp]# chmod 600 testing/testing <==变更权限
[root@study tmp]# ls -ald testing testing/testing
drwxr--r--. 2 root root 20 Jun 3 01:00 testing
-rw-------. 1 root root 0 Jun 3 01:00 testing/testing

cd：变换目录

pwd：显示当前目录

rmdir：删除一个空的目录

mkdir -p 可创建多层目录

-m 可直接设置目录权限

mkdir+目录名 创建新目录

touch +目录+文件名 创建新的文件夹

6. 文件名称
文件名称的开头为小数点“.”时, 代表这文件名称的开头为小数点“.”时, 代表这
个文件为“隐藏文件”
? > < ; & ! [ ] | \ ’ " ` ( ) { }±最好避免

7. 三层目录
/ (root, 根目录):与开机系统有关;
/usr (unix software resource):与软件安装/执行有关;
/var (variable):与系统运行过程有关。