全新的知识哇！超兴奋~
今天的主要任务，是初步认识Linux操作系统

关于Linux

久闻大名，凭借我在阅读 生信小白第一天-0成本召唤linux之前的了解的话

唔...好像是个操作系统
小企鹅！！！

Linux

读完之后

确实是个操作系统！
不过~~
【发动技能·一句话总结】
Linux是一款主要承载于苏坡肯piu特（supercomputer），支持多用户使用但单用户权限严格受限，拥有树状文件系统并通过命令行来实现操作的强大操作系统

1.下载并使用Xshellhe和ubuntu

链接和教程快去关注公众号生信星球啦【无利益相关安利哦~

TIPS

登陆失败记得检查IP地址、用户名、密码和网络状况哦~

2.初识Linux命令行

课程中总结出了非常常用的9个命令
pwd mkdir ls rm cd vi cat cp mv
ps：在初级指令后可以附加指令，会有额外的操作效果，信息量太大复制粘贴来留存备用，也备份了.txt，待慢慢尝试

2.1 pwd命令

输出当前工作目录的名称

2.1.1 pwd l（默认）

print the value of $PWD if it names the current working directory

2.1.2 pwd p

print the physical directory, without any symbolic links

2.2 mkdir

创建一个新的目录（具体微操没太看懂）

-m, --mode=MODE set file mode (as in chmod), not a=rwx - umask
-p, --parents no error if existing, make parent directories as needed
-v, --verbose print a message for each created directory
-Z set SELinux security context of each created directory
to the default type
--context[=CTX] like -Z, or if CTX is specified then set the SELinux
or SMACK security context to CTX
--version output version information and exit

2.3 ls

列出当前目录的所有信息，默认按照字母顺序排序条目。可以用 -cftuvSUX（不理解有待搜索）或者--排序

-a, --all do not ignore entries starting with .
-A, --almost-all do not list implied . and ..
--author with -l, print the author of each file
-b, --escape print C-style escapes for nongraphic characters
--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 like -l, but do not list owner
--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 use a long listing format
-L, --dereference when showing file information for a symbolic
link, show information for the file the link
references rather than for the link itself
-m fill width with a comma separated list of entries
-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 reverse order while sorting
-R, --recursive list subdirectories recursively
-s, --size print the allocated size of each file, in blocks
-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 FORMAT1<newline>FORMAT2, 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 display this help and exit
--version output version information and exit

2.4 rm

将文件移除或者取消关联

-f, --force ignore nonexistent files and arguments, never prompt
-i prompt before every removal
-I prompt once before removing more than three files, or
when removing recursively; less intrusive than -i,
while still giving protection against most mistakes
--interactive[=WHEN] prompt according to WHEN: never, once (-I), or
always (-i); without WHEN, prompt always
--one-file-system when removing a hierarchy recursively, skip any
directory that is on a file system different from
that of the corresponding command line argument
--no-preserve-root do not treat '/' specially
--preserve-root do not remove '/' (default)
-r, -R, --recursive remove directories and their contents recursively
-d, --dir remove empty directories
-v, --verbose explain what is being done
--help display this help and exit
--version output version information and exit
By default, rm does not remove directories. Use the --recursive (-r or -R)
option to remove each listed directory, too, along with all of its contents.
To remove a file whose name starts with a '-', for example '-foo',
use one of these commands:
rm -- -foo
rm ./-foo
Note that if you use rm to remove a file, it might be possible to recover
some of its contents, given sufficient expertise and/or time. For greater
assurance that the contents are truly unrecoverable, consider using shred.

2.5 cd

cd+目录 ——进入某个目录
cd+- ——返回上级目录
cd或cd~ ——返回总根目录

Change the shell working directory.
Change the current directory to DIR. The default DIR is the value of the
HOME shell variable.
The variable CDPATH defines the search path for the directory containing
DIR. Alternative directory names in CDPATH are separated by a colon (:).
A null directory name is the same as the current directory. If DIR begins
with a slash (/), then CDPATH is not used.
If the directory is not found, and the shell option cdable_vars is set,
the word is assumed to be a variable name. If that variable has a value,
its value is used for DIR.
Options:
-L force symbolic links to be followed: resolve symbolic
links in DIR after processing instances of ..'
-P use the physical directory structure without following
symbolic links: resolve symbolic links in DIR before
processing instances of ..'
-e if the -P option is supplied, and the current working
directory cannot be determined successfully, exit with
a non-zero status
-@ on systems that support it, present a file with extended
attributes as a directory containing the file attributes
The default is to follow symbolic links, as if -L' were specified.
`..' is processed by removing the immediately previous pathname component
back to a slash or the beginning of DIR.
Exit Status:
Returns 0 if the directory is changed, and if $PWD is set successfully when
-P is used; non-zero otherwise.

2. 6vi

新建脚本或者文本文档
英文输入法按i键输入
Esc退出编辑模式
左下角输入:x 保存并退出

usage: vim [arguments] [file ..] edit specified file(s)
or: vim [arguments] - read text from stdin
or: vim [arguments] -t tag edit file where tag is defined
or: vim [arguments] -q [errorfile] edit file with first error
Arguments:
-- Only file names after this
-v Vi mode (like "vi")
-e Ex mode (like "ex")
-E Improved Ex mode
-s Silent (batch) mode (only for "ex")
-d Diff mode (like "vimdiff")
-y Easy mode (like "evim", modeless)
-R Readonly mode (like "view")
-Z Restricted mode (like "rvim")
-m Modifications (writing files) not allowed
-M Modifications in text not allowed
-b Binary mode
-l Lisp mode
-C Compatible with Vi: 'compatible'
-N Not fully Vi compatible: 'nocompatible'
-V[N][fname] Be verbose [level N] [log messages to fname]
-D Debugging mode
-n No swap file, use memory only
-r List swap files and exit
-r (with file name) Recover crashed session
-L Same as -r
-A start in Arabic mode
-H Start in Hebrew mode
-F Start in Farsi mode
-T <terminal> Set terminal type to <terminal>
--not-a-term Skip warning for input/output not being a terminal
--ttyfail Exit if input or output is not a terminal
-u <vimrc> Use <vimrc> instead of any .vimrc
--noplugin Don't load plugin scripts
-p[N] Open N tab pages (default: one for each file)
-o[N] Open N windows (default: one for each file)
-O[N] Like -o but split vertically
+Start at end of file
+<lnum> Start at line <lnum>
--cmd <command> Execute <command> before loading any vimrc file
-c <command> Execute <command> after loading the first file
-S <session> Source file <session> after loading the first file
-s <scriptin> Read Normal mode commands from file <scriptin>
-w <scriptout> Append all typed commands to file <scriptout>
-W <scriptout> Write all typed commands to file <scriptout>
-x Edit encrypted files
--startuptime <file> Write startup timing messages to <file>
-i <viminfo> Use <viminfo> instead of .viminfo
--clean 'nocompatible', Vim defaults, no plugins, no viminfo
-h or --help Print Help (this message) and exit
--version Print version information and exit

2. 7cat

查看文本文档
head 输出前10行
tail输出后10行
后面加上-n自定义输出几行
ps:-n与head之间有空格，-n和数字之间空格可有可无

Concatenate FILE(s) to standard output.
With no FILE, or when FILE is -, read standard input.
-A, --show-all equivalent to -vET #和
-b, --number-nonblank number nonempty output lines, overrides -n
-e equivalent to -vE
-E, --show-ends display $ at end of each line
-n, --number number all output lines
-s, --squeeze-blank suppress repeated empty output lines
-t equivalent to -vT
-T, --show-tabs display TAB characters as ^I
-u (ignored)
-v, --show-nonprinting use ^ and M- notation, except for LFD and TAB
--help display this help and exit
--version output version information and exit
Examples:
cat f - g Output f's contents, then standard input, then g's contents.
cat Copy standard input to standard output.

2. 8 cp

复制文件
格式：cp a b【复制a命名为b】

Usage: cp [OPTION]... [-T] SOURCE DEST
or: cp [OPTION]... SOURCE... DIRECTORY
or: cp [OPTION]... -t DIRECTORY SOURCE...
Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
Mandatory arguments to long options are mandatory for short options too.
-a, --archive same as -dR --preserve=all
--attributes-only don't copy the file data, just the attributes
--backup[=CONTROL] make a backup of each existing destination file
-b like --backup but does not accept an argument
--copy-contents copy contents of special files when recursive
-d same as --no-dereference --preserve=links
-f, --force if an existing destination file cannot be
opened, remove it and try again (this option
is ignored when the -n option is also used)
-i, --interactive prompt before overwrite (overrides a previous -n
option)
-H follow command-line symbolic links in SOURCE
-l, --link hard link files instead of copying
-L, --dereference always follow symbolic links in SOURCE
-n, --no-clobber do not overwrite an existing file (overrides
a previous -i option)
-P, --no-dereference never follow symbolic links in SOURCE
-p same as --preserve=mode,ownership,timestamps
--preserve[=ATTR_LIST] preserve the specified attributes (default:
mode,ownership,timestamps), if possible
additional attributes: context, links, xattr,
all
--no-preserve=ATTR_LIST don't preserve the specified attributes
--parents use full source file name under DIRECTORY
-R, -r, --recursive copy directories recursively
--reflink[=WHEN] control clone/CoW copies. See below
--remove-destination remove each existing destination file before
attempting to open it (contrast with --force)
--sparse=WHEN control creation of sparse files. See below
--strip-trailing-slashes remove any trailing slashes from each SOURCE
argument
-s, --symbolic-link make symbolic links instead of copying
-S, --suffix=SUFFIX override the usual backup suffix
-t, --target-directory=DIRECTORY copy all SOURCE arguments into DIRECTORY
-T, --no-target-directory treat DEST as a normal file
-u, --update copy only when the SOURCE file is newer
than the destination file or when the
destination file is missing
-v, --verbose explain what is being done
-x, --one-file-system stay on this file system
-Z set SELinux security context of destination
file to default type
--context[=CTX] like -Z, or if CTX is specified then set the
SELinux or SMACK security context to CTX
--help display this help and exit
--version output version information and exit
By default, sparse SOURCE files are detected by a crude heuristic and the
corresponding DEST file is made sparse as well. That is the behavior
selected by --sparse=auto. Specify --sparse=always to create a sparse DEST
file whenever the SOURCE file contains a long enough sequence of zero bytes.
Use --sparse=never to inhibit creation of sparse files.
When --reflink[=always] is specified, perform a lightweight copy, where the
data blocks are copied only when modified. If this is not possible the copy
fails, or if --reflink=auto is specified, fall back to a standard copy.
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable. Here are the values:
none, off never make backups (even if --backup is given)
numbered, t make numbered backups
existing, nil numbered if numbered backups exist, simple otherwise
simple, never always make simple backups
As a special case, cp makes a backup of SOURCE when the force and backup
options are given and SOURCE and DEST are the same name for an existing,
regular file.

2. 9 mv

mv 将文件移入文件夹，或者重命名
mv file 路径是移动file到某路径下
mv file1 file2是将file1重命名为file2

Mandatory arguments to long options are mandatory for short options too.
--backup[=CONTROL] make a backup of each existing destination file
-b like --backup but does not accept an argument
-f, --force do not prompt before overwriting
-i, --interactive prompt before overwrite
-n, --no-clobber do not overwrite an existing file
If you specify more than one of -i, -f, -n, only the final one takes effect.
--strip-trailing-slashes remove any trailing slashes from each SOURCE
argument
-S, --suffix=SUFFIX override the usual backup suffix
-t, --target-directory=DIRECTORY move all SOURCE arguments into DIRECTORY
-T, --no-target-directory treat DEST as a normal file
-u, --update move only when the SOURCE file is newer
than the destination file or when the
destination file is missing
-v, --verbose explain what is being done
-Z, --context set SELinux security context of destination
file to default type
--help display this help and exit
--version output version information and exit
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable. Here are the values:
none, off never make backups (even if --backup is given)
numbered, t make numbered backups
existing, nil numbered if numbered backups exist, simple otherwise
simple, never always make simple backups