CS-Notes/notes/Linux.md

<!-- GFM-TOC -->
* [???¨°??????????](#???¨°??????????)
    * [????](#????)
    * [???](#???)
    * [??????](#??????)
    * [?????](#?????)
    * [PATH](#path)
    * [???§Ö??](#???§Ö??)
    * [sudo](#sudo)
    * [GNU](#gnu)
    * [????????](#????????)
    * [???????§Ñ·Ú](#???????§Ñ·Ú)
* [????](#????)
    * [??????????](#??????????)
    * [??????](#??????)
        * [1. MBR](#1-mbr)
        * [2. GPT](#2-gpt)
    * [??????????](#??????????)
        * [1. BIOS](#1-bios)
        * [2. UEFI](#2-uefi)
    * [????](#????)
* [??????????????](#??????????????)
    * [?????????](#?????????)
    * [?????????????????](#?????????????????)
        * [1. ?????????????](#1-?????????????)
        * [2. ???????????](#2-???????????)
        * [3. ??????](#3-??????)
    * [???????](#???????)
    * [?????????](#?????????)
    * [??????](#??????)
* [???????](#???????)
    * [??????](#??????)
    * [????????????????](#????????????????)
        * [1. ls](#1-ls)
        * [2. cp](#2-cp)
        * [3. rm](#3-rm)
        * [4. mv](#4-mv)
    * [??????????](#??????????)
        * [1. cat](#1-cat)
        * [2. tac](#2-tac)
        * [3. more](#3-more)
        * [4. less](#4-less)
        * [5. head](#5-head)
        * [6. tail](#6-tail)
        * [7. od](#7-od)
        * [8. touch](#8-touch)
    * [????????????](#????????????)
        * [1. which](#1-which)
        * [2. whereis](#2-whereis)
        * [3. locate](#3-locate)
        * [4. find](#4-find)
            * [4.1 ??????§Û?????](#41-??????§Û?????)
            * [4.2 ???????????????????§Û?????](#42-???????????????????§Û?????)
            * [4.3 ??????????????§Û?????](#43-??????????????§Û?????)
* [???????????](#???????????)
    * [??????????](#??????????)
    * [inode](#inode)
    * [???? inode ?? block](#????-inode-??-block)
    * [????????????????](#????????????????)
        * [1. ???????](#1-???????)
        * [2. ????????](#2-????????)
* [???????](#???????)
    * [???](#???)
        * [1. gzip](#1-gzip)
        * [2. bzip2](#2-bzip2)
        * [3. xz](#3-xz)
    * [???](#???)
* [BASH](#bash)
    * [Bash????](#bash????)
    * [????????](#????????)
    * [??????????](#??????????)
    * [???????????](#???????????)
    * [???????](#???????)
        * [1. ??????cut](#1-??????cut)
        * [2. ????????sort??uniq](#2-????????sort??uniq)
        * [3. ???????????tee](#3-???????????tee)
        * [4. ?????????tr??col??expand??join??paste](#4-?????????tr??col??expand??join??paste)
        * [5. ???????split](#5-???????split)
* [??????????????????????](#??????????????????????)
    * [grep](#grep)
    * [printf](#printf)
    * [awk](#awk)
* [vim ??????](#vim-??????)
* [?¦Ï?????](#?¦Ï?????)
<!-- GFM-TOC -->

# ???¨°??????????

## ????

**1. --help**

????????¡Â??????????

**2. man**

man ?? manual ????§Õ???????????????????????

????? man date ????? DATE(1) ????????§Ö??????????????????????????????????????

| ???? | ???? |
| -- | -- |
| 1 | ????? shell ?????§á????????????????????? |
| 5 | ??????? |
| 8 | ????????????????????? |

**3. info**

info ?? man ????????? info ???????????????—¨?????????????????

## ???

**1. ???????§Õ????? sync**

?????????????????§Õ????¦Ë??????§Ö?????????????????????????????????????????? sync ?????????

**2. shutdown**

```html
# /sbin/shutdown [-krhc] [???] [??????]
-k ?? ???????????????????????????????????
-r ?? ???????????????????????
-h ?? ??????????????????????
-c ?? ??????????§Ö? shutdown ???????
```

**3. ??????????**

reboot??halt??poweroff??

## ??????

ps ??þŸ

????? theadx ??????????

```html
ps aux | grep threadx
```

## ?????

netstat ??þŸ

???????? 80 ???????

```html
netstat -anp | grep 80
```

## PATH

????????????? PATH ????????????????¡¤????¡¤??????? : ?????

```html
/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/dmtsai/.local/bin:/home/dmtsai/bin
```

## ???§Ö??

0???????
1????????????????????root????
2??????????????????
3??????????????????????????????????????????
4????????¦Ä???
5???????????? X-windows ??????????????—¥
6????????????????????

## sudo

??? sudo ????????????? root ????§Ö????þŸ????????? /etc/sudoers ?§Ó?????????þŸ

## GNU

GNU ????????????¨±?????????????????????????????????????? GNU???????????????? GPL ????????????? GPL ???? GNU ??¨´??????§¿?ï…???????????????

- ???¦Ê???????§Õ??????????
- ???????????
- ?????????????????????????¨À?

## ????????

RPM ?? DPKG ???????????????????????RPM ???? Redhat Package Manager???????? Red Hat ????????????? GNU ???????????????????? Linux ?? (RHEL) ?????????????? RPM ???§à?????????? Debian ?????? (UBUNTU) ?? DEB ???????????? DPKG?????? Debian Package??????????? RPM ?????

YUM ???? RPM ?????????????????????????????????????????????????? RPM ???????????????????????????????????????????????????????????????????????????????????????????????????YUM ???????????????????????????????????

## ???????§Ñ·Ú

Linux ???§Ñ??????????? Linux ????????????????

**???? DPKG**

??????§Ñ?

- Ubuntu

???????§Ñ?

- Debian

**???? RPM**

??????§Ñ?

- Red Hat

???????§Ñ?

- Fedora
- CentOS

# ????

## ??????????

Linux ????????????????????????

????????????????

- SCSI/SATA/USB ?????/dev/sd[a-p]
- IDE ?????/dev/hd[a-d]

??????????????????????????????????§Û??????????????????¦Ë??????

## ??????

?????????????????????????????????? MBR ???????????????????????? GPT ??????

### 1. MBR

MBR ?§µ??????????????????????§µ?????????????Master boot record, MBR??????????partition table???????? MBR ? 446 bytes??partition table ? 64 bytes??

????????? 64 bytes????????›¥ 4 ?????????? 4 ???????????????Primary?????????????Extended?????????????????????????????????????????????????????????????????????????????????????????????§»????????????????

Linux ???????????????????????????????????????????+???????? /dev/sda1????????????????? 5 ?????

### 2. GPT

?????????§Ó??????????§³?????? 512bytes ?????????? 4k??GPT ?????????§Õ?????????????????????????????Logical Block Address, LBA????

GPT ?? 1 ?????????? MBR?????????? 33 ????????????????????????? 33 ????????????????????§Ò????

GPT ????????????????????????????????? 128 ????????

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/a5c25452-6fa5-49e7-9322-823077442775.jpg)

## ??????????

### 1. BIOS

BIOS ????????????????§Ö??????????????????????????????????????????????????? MBR???? MBR ??????§Ö?????????????????????????????????????????????

MBR ?§Ö????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? MBR ?§Ö???????????????????????????????????????????????????????????????????????????????

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/f900f266-a323-42b2-bc43-218fdb8811a8.jpg)

???????????????????? Windows ???? Linux???????? Windows ?????? MBR???? Linux ???????????????????? MBR ???????????????????????????????????????????????????

### 2. UEFI

UEFI ????? BIOS ???????????—¨?????????

## ????

?????????????????????????????????????????????????????????

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/249f3bb1-feee-4805-a259-a72699d638ca.jpg)

# ??????????????

## ?????????

?????????????????????????????????????????????§Ó???????????

??? ls ????????????????????????????????? drwxr-xr-x. 3 root root 17 May 6 00:14 .config????????????????????

- drwxr-xr-x?????????????????? 1 ¦Ë??????????¦²??? 9 ¦Ë?????????¦±?
- 3??????????
- root???????????
- root????????ï”
- 17???????§³??
- May 6 00:14???????????????
- .config?????????

???????????????¾©???§µ?

- d??????
- -???????
- l???????????

9 ¦Ë????????????§µ?? 3 ?????ï…?? 3 ?ï…??????????????????????????????????????????????????§Ö? 3 ¦Ë???? r??w??x ??????????????§Õ??????§³?

## ?????????????????

### 1. ?????????????

```html
# chgrp [-R] groupname dirname/filename
-R????????
```

### 2. ???????????

?????????????????????????????????????î•

```html
# chown [-R] ?????:????? dirname/filename
```

### 3. ??????

?????????????????????????????????? 3 ??¦Ë???????????????¦Ë???????????¦Ë????? 4??2??1????????????????????? r??4??w??2??x??1??

```html
# chmod [-R] xyz dirname/filename
```

???????? .bashrc ???????????? -rwxr-xr--??

```html
# chmod 754 .bashrc
```

???????¡Â??????Ú…????

```html
# chmod [ugoa]  [+-=] [rwx] dirname/filename
- u???????
- g?????????
- o????????
- a????????
- +????????
- -????????
- =???Ú…???
```

??????? .bashrc ???????????????§Õ????

```html
# chmod a+w .bashrc
```

## ???????

?????????›¥???????????????§µ?????›¥????????????????§³????????????? w ??????????????????????

???›¥????§Ò???????????????????????§Ò?????????????? r ???????????????§Ò?w ????????????????§Ò????????????????????????????????????????x ??????????????????????x ????? r ?? w ??????????????????????????????????????????????§Ò??????????§Ò??????????

## ?????????

??????????????????§á???????????? 666 ??????? -rw-rw-rw- ??
?????????????????????????????????§á???????????? 777 ??????? drwxrwxrwx??

??????? umask ???????????????????????????????????????????? 002 ??????????????????????? 2 ???????????§Õ???????????????????????? -rw-rw-r-- ??

## ??????

??????? Linux ???§Ñ·Ú????????????????Filesystem Hierarchy Standard (FHS) ?ÕÇ?? Linux ??????????????????????????

- / (root, ????)
- /usr (unix software resource)????????????????????????????
- /var (variable)???????????????§Û????§Ö??????????

???????????????

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/27ace615-558f-4dfb-8ad4-7ac769c10118.jpg)

# ???????

## ??????

1. modification time (mtime)????????????????????
2. status time (ctime)??????????????????????????????
3. access time (atime)????????????????

## ????????????????

### 1. ls

?§Ô???????????????????????????????§Ñ??????????

```html
# ls [-aAdfFhilnrRSt] file|dir
-a ???§Ô?????????
-d ?????§Ô???????
-l ?????????????§Ô???????????????????????????
```

### 2. cp

?????????

?????????????????????????????????????§³?

```html
cp [-adfilprsu] source destination
-a ?????? -dr --preserve=all ??????????? dr ??¦Ï????????
-d ?????????????????????????????????????????????
-i ?????????????????????????????????
-p ?????????????????????
-r ????????????
-u ??destination ?? source ?????? destination???? destination ????????????????
--preserve=all ?????? -p ??????????????????? SELinux ??????, links, xattr ?????????
```

### 3. rm

?????????

```html
# rm [-fir] ???????
-r ????????
```

### 4. mv

?????????

```html
# mv [-fiu] source destination
# mv [options] source1 source2 source3 .... directory
-f ?? force ????????????????????????????????????????
```

## ??????????

### 1. cat

???????????

```html
# cat [-AbEnTv] filename
-n ????????§Ü?? ??????????????§Ü???? -b ??????
```

### 2. tac

?? cat ?????????????????§á???????

### 3. more

????????????????????????????????

### 4. less

?? more ?????

### 5. head

??????????????§³?

```html
# head [-n number] filename
-n ??????????????????????§Ö????
```

### 6. tail

?? head ????????????????????§³?

### 7. od

??????????????????????????????????????

### 8. touch

??????????????????????

```html
# touch [-acdmt] filename
-a ?? ???? atime
-c ?? ???? ctime?????????????????????????
-m ?? ???? mtime
-d ?? ????????????????????????????????????????? --date="????????"
-t ????????????????????????????????????[YYYYMMDDhhmm]
```

## ????????????

### 1. which

?????????

```html
# which [-a] command
-a ????????????§Ô???????????§Ö????
```

### 2. whereis

whereis ??????????????????????????????????????

```html
# whereis [-bmsu] dirname/filename
```

### 3. locate

locate ?????¨´????????????????????????

locate ??? /var/lib/mlocate/ ???????????????????????›¥??????§µ?????????????¦²?????????? locate ????????????????????? updatedb ???????????????

```html
# locate [-ir] keyword
-r???????????
```

### 4. find

find ?????????????????????????????

```html
# find filename [option]
```

#### 4.1 ??????§Û?????

```html
-mtime  n ???§Ô??? n ??????????????????????
-mtime +n ???§Ô??? n ????(???? n ????)????????????
-mtime -n ???§Ô??? n ?????(?? n ????)????????????
-newer file ?? ?§Ô??? file ????????
```

+4??4 ?? -4 ?????????¦¶?????

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/658fc5e7-79c0-4247-9445-d69bf194c539.png)

#### 4.2 ???????????????????§Û?????

```html
-uid n
-gid n
-user name
-group name
-nouser ???????????????? /etc/passwd ?????
-nogroup????????????öö?????? /etc/group ?????
```

#### 4.3 ??????????????§Û?????

```html
-name filename
-size [+-]SIZE??????? SIZE ?????(+)??§³(-)?????????? SIZE ?????§µ?c: ???? byte??k: ???? 1024bytes??????????? 50KB??????????????? -size +50k
-type TYPE
-perm mode  ???????????? mode ?????
-perm -mode ???????????? mode ?????
-perm /mode ??????????????? mode ?????
```

# ???????????

## ??????????

????????§Ú????????????????????????????????????????????????????????????????§Ö???????????????????????????????????????????????????????????????????

???????????????????

1. superblock????????????????????????? inode ?? block ?????????????????????????????????????????????
2. inode?????????????? inode???????????????????????????????????? block ????
3. block????????????????????????????????? block??

????????????????????????? inode ??????????????????????? block?????????? block ?????????????

????????????????????????? block ????????

Ext2 ???????????????????????????????????? block ????????????????????????????? block ??ï…???????

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/1974a836-aa6b-4fb8-bce1-6eb11969284a.jpg)

## inode

Ext2 ????????? block ??§³?? 1k??2k ?? 4k ?????????? block ??§³??????????????§³??????? inode ??§³????? 128 bytes??

inode ?§Þ???????????????? block????????? block ???§³?????????????????????? block??????? inode ??§³???????????????????? block?????????????????????????????????? block ???????§³????????? block ?????????????? block??

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/89091427-7b2b-4923-aff6-44681319a8aa.jpg)

inode ????????????????

- ???????????(read/write/excute)??
- ?????????????????(owner/group)??
- ?????????????
- ????????????????????(ctime)??
- ?????¦Å??????(atime)??
- ??????????(mtime)??
- ???????????????(flag)???? SetUID...??
- ????????????????? (pointer)??

## ???? inode ?? block

???????????????????? inode ????????? block??block ???????????????????????? inode ????????????????????????? inode ???????????????????????????§µ????????????????????????????????§»?????????? w ????§Û??

## ????????????????

```html
# ln [-sf] source_filename dist_filename
-s ??????? hard link???? -s ? symbolic link
-f ????????5?????????????????????
```

### 1. ???????

hard link ?????????????????????????????????????????????? inode ?????????????????????????????????????????? 0??

????????????????? Filesystem??????????????????

```html
# ln /etc/crontab .
# ll -i /etc/crontab crontab
34474855 -rw-r--r--. 2 root root 451 Jun 10 2014 crontab
34474855 -rw-r--r--. 2 root root 451 Jun 10 2014 /etc/crontab
```

### 2. ????????

symbolic link ???????? Windows ????????????????????????????????????????????????????????????????????????????????????????

symbolic link ????????????????

```html
# ll -i /etc/crontab /root/crontab2
34474855 -rw-r--r--. 2 root root 451 Jun 10 2014 /etc/crontab
53745909 lrwxrwxrwx. 1 root root 12 Jun 23 22:31 /root/crontab2 -> /etc/crontab
```

# ???????

## ???

Linux ?????§Ü????????????????????????????

| ????? | ??????? |
| -- | -- |
| \*.Z | compress |
|\*.zip |  zip |
|\*.gz  | gzip|
|\*.bz2 |  bzip2 |
|\*.xz  | xz |
|\*.tar |  tar ???????????????§à?????? |
|\*.tar.gz | tar ????????????????? gzip ????? |
|\*.tar.bz2 | tar ????????????????? bzip2 ????? |
|\*.tar.xz | tar ????????????????? xz ????? |

### 1. gzip

gzip ?? Linux ?????????????????? compress??zip ?? gzip ????????????

???? gzip ?????????????????????

?? 9 ???????????????????¨¢?

??????? zcat??zmore??zless ??????????????????

```html
$ gzip [-cdtv#] filename
-c ???????????????????????
-d ???????
-t ??????????????????
-v ??????????????
-# ?? # ???????????????????????????????????????????6
```

### 2. bzip2

???? gzip ???????????

??????bzcat??bzmore??bzless??bzgrep??

```html
$ bzip2 [-cdkzv#] filename
-k ??????????
```

### 3. xz

???? bzip2 ???????????

?????????gzip??bzip2??xz ??????????????????????????????????????????????

??????xzcat??xzmore??xzless??xzgrep??

```html
$ xz [-dtlkc#] filename
```

## ???

????????????????????????????????????????????????????????tar ???????????????????????? gip??bzip2??xz ?????????????????

```html
$ tar [-z|-j|-J] [cv] [-f ?????tar???] filename...  ==??????
$ tar [-z|-j|-J] [tv] [-f ???§Ö?tar???]              ==??
$ tar [-z|-j|-J] [xv] [-f ???§Ö?tar???] [-C ??]    ==?????
-z ?????zip??
-j ?????bzip2??
-J ?????xz??
-c ?????????????
-t ??????????????????§»?????
-x ??????????????????
-v ???????/???????????§µ???????????????????
-f : filename?????????????
-C ?? ?? ??????????????
```

????????????

?????? ?? tar -jcv -f filename.tar.bz2 ???????????????????
?? ??&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;?? tar -jtv -f filename.tar.bz2
?????&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;??tar -jxv -f filename.tar.bz2 -C ??????????

# BASH

??????? shell ?????????????Bash ???? shell ??????

## Bash????

**1. ???????**

?????¨´??????þŸ???¦Å??????§Ö??????????????????§µ? \~/.bash_history ????§Þ?????????¦Å??????§Û??????þŸ

**2. ????????????**

??????tab

**3. ????????**

???? lm ?? ls -al ???????

**4. shell scripts**

**5. ????**

???? ls -l /usr/bin/X\* ?§Ô? /usr/bin ?????????? X ??????????

## ????????

?????????????????? = ??????????????????????? \$ ????????? \${} ????????????????? echo ???þŸ

```bash
$ var=abc
$ echo $var
$ echo ${var}
```

????????????§á????????????????????????????????????????????????????????var="lang is \$LANG"????var???? lang is zh_TW.UTF-8??????????????????????????????????????? var='lang is \$LANG'???? var ???? lang is \$LANG??


??????? \`???\` ???? \$(???) ????????????§ß????????????????? version=\$(uname -r)???? version ???? 3.10.0-229.el7.x86_64??

??????? export ???????????????????????????????????????????????????¦Í???????????? Bash ?????????? Bash??

Bash ?????????????????????????????????????????§Ú?????????????????????????????????????????????????? declare ????

```html
$ declare [-aixr] variable
-a ?? ?????????????
-i ?? ?????????????
-x ?? ?????????????
-r ?? ?????readonly????
```

??? [ ] ??????????§Ó?????

```bash
$ array[1]=a
$ array[2]=b
$ echo ${array[1]}
```

## ??????????

1. ?????????¡¤?????????????? /bin/ls ???? ./ls ??
2. ?????????????????§µ?
3. ?? Bash ????????????§µ?
4. ?? \$PATH ?????????????¡¤??????????????????????§³?

## ???????????

???????????????????????????????????????????

1. ??????? (stdin) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;??????? 0 ????? < ?? << ??
2. ?????? (stdout)&nbsp;&nbsp;&nbsp;&nbsp;??????? 1 ????? > ?? >> ??
3. ??????????(stderr)??????? 2 ????? 2> ?? 2>> ??

???§µ?????????????????????????????????????????????????????

??????????????????????????????????? /dev/null ???????????????

??????????????????????????????????????????????????????????????????????? 2>&1 ???????????????????????????

```bash
$ find /home -name .bashrc > list 2>&1
```

## ???????

??????????????????????????????????????????????????????????????????????????????????????????¨´???????????????? | ??????????????þŸ

```bash
$ ls -al /etc | less
```

### 1. ??????cut

????????????§Ö???§³?

cut ??????????§Ù??????????????

```html
$ cut
-d ???????
-f ?????? -d ???????? -f n ????? n ??????
-c ??????????¦Ë???????
```

????1??last ????????????????????????????????

```html
$ last
root pts/1 192.168.201.101 Sat Feb 7 12:35 still logged in
root pts/1 192.168.201.101 Fri Feb 6 12:13 - 18:46 (06:33)
root pts/1 192.168.201.254 Thu Feb 5 22:37 - 23:53 (01:16)

$ last | cut -d ' ' -f 1
```

????2???? export ????????????? 12 ??????????????????

```html
$ export
declare -x HISTCONTROL="ignoredups"
declare -x HISTSIZE="1000"
declare -x HOME="/home/dmtsai"
declare -x HOSTNAME="study.centos.vbird"
.....(???????).....

$ export | cut -c 12
```

### 2. ????????sort??uniq

**sort** ????????

```html
$ sort [-fbMnrtuk] [file or stdin]
-f ???????§³§Õ
-b ??????????????
-M ?????¡¤???????????????? JAN, DEC
-n ?????????
-r ??????????
-u ?????? unique ?????????????????
-t ?????????????tab
-k ??????????????
```

??????/etc/passwd ???????? : ?????????????????????

```html
$ cat /etc/passwd | sort -t ':' -k 3
root:x:0:0:root:/root:/bin/bash
dmtsai:x:1000:1000:dmtsai:/home/dmtsai:/bin/bash
alex:x:1001:1002::/home/alex:/bin/bash
arod:x:1002:1003::/home/arod:/bin/bash
```

**uniq** ?????????????????????

```html
$ uniq [-ic]
-i ???????§³§Õ
-c ?????§Þ???
```

??????????????????????

```html
$ last | cut -d ' ' -f 1 | sort | uniq -c
1
6 (unknown
47 dmtsai
4 reboot
7 root
1 wtmp
```

### 3. ???????????tee

?????????????????????????§µ??? **tee** ??????????????????????????????????????????????? tee ?????????????????????????????

```html
$ tee [-a] file
```

### 4. ?????????tr??col??expand??join??paste

 **tr** ???????????§Ö???????????????????<3F>I??

```html
$ tr [-ds] SET1 ...
-d ?? ??????? SET1 ????????
```

???????? last ????????????§³§Õ??????§Õ??

```html
$ last | tr '[a-z]' '[A-Z]'
```

 **col** ?? tab ?????????????

```html
$ col [-xb]
-x ?? ?? tab ?????????????
```

**expand** ?? tab ??????????????????? 8 ????

```html
$ expand [-t] file
-t ??tab ??????????
```

**join** ????????????????§Ü???????

```html
$ join [-ti12] file1 file2
-t ????????????????
-i ???????§³§Õ?????
-1 ????????????????????
-2 ????????????????????
```

**paste** ????????????????

```html
$ paste [-d] file1 file2
-d ????????????? tab
```

### 5. ???????split

**split** ????????????????????

```html
$ split [-bl] file PREFIX
-b ?????§³?????§Ù?????????¦Ë?????? b, k, m ??
-l ?????????????§Ù?????
- PREFIX ??????????????????
```

# ??????????????????????

## grep

???????????????????????????

```html
$ grep [-acinv] [--color=auto] ???????? filename
-a ?? ?? binary ????? text ??????????????
-c ?? ???????????
-i ?? ?????§³§Õ
-n ?? ????§Ü?
-v ?? ????????????????? ???????? ??????????
--color=auto ??????????????????
```

??????????? the ??????????????????????????? --color=auto ???????????????? Linux ?????????? the ???????

```html
$ grep -n 'the' regular_express.txt
8:I can't finish the test.
12:the symbol '*' is represented as start.
15:You are the best is mean you are the no. 1.
16:The world Happy is the same with "glad".
18:google is the best tools for search keyword
```

??? { ?? } ??????? shell ???????????????????????????????????????‰^

```html
$ grep -n 'go\{2,5\}g' regular_express.txt
```

?????????????¦Ï? [???????](https://github.com/00000H/notes/blob/master/notes/%E6%AD%A3%E5%88%99%E8%A1%A8%E8%BE%BE%E5%BC%8F.md).

## printf

?????????????

????????????????? printf ????????????? $( ) ?????

```html
$ printf '%10s %5i %5i %5i %8.2f \n' $(cat printf.txt)
    DmTsai    80    60    92    77.33
     VBird    75    55    80    70.00
       Ken    60    90    70    73.33
```

## awk

```html
$ awk '???????? 1{???? 1} ???????? 2{???? 2} ...' filename
```

awk ??¦Ä?????§µ????????§³??¦Ë????¦²??????¦Å???????????\$n??n ???¦Ê???? 1 ?????\$0 ???????§³?

???? 1???????????????????? ip

```html
$ last -n 5
dmtsai pts/0 192.168.1.100 Tue Jul 14 17:32 still logged in
dmtsai pts/0 192.168.1.100 Thu Jul 9 23:36 - 02:58 (03:22)
dmtsai pts/0 192.168.1.100 Thu Jul 9 17:23 - 23:36 (06:12)
dmtsai pts/0 192.168.1.100 Thu Jul 9 08:02 - 08:17 (00:14)
dmtsai tty1 Fri May 29 11:55 - 12:11 (00:15)

$ last -n 5 | awk '{print $1 "\t" $3}
```

awk ??????

| ???????? | ???????? |
| -- | -- |
| NF | ??????§Ö???????? |
| NR | ??????????????????? |
| FS | ??????????????????? |

???? 2??????????????§Ü????????????§Ø??????

```html
$ last -n 5 | awk '{print $1 "\t lines: " NR "\t columns: " NF}'
dmtsai lines: 1 columns: 10
dmtsai lines: 2 columns: 10
dmtsai lines: 3 columns: 10
dmtsai lines: 4 columns: 10
dmtsai lines: 5 columns: 9
```

?????????????????????§Ö?????? ==??

???? 3??/etc/passwd ????????????? UID???? UID §³?? 10 ????????§Õ???

```text
cat /etc/passwd | awk 'BEGIN {FS=":"} $3 < 10 {print $1 "\t " $3}'
root 0
bin 1
daemon 2
```

# vim ??????

![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/341c632a-1fc1-4068-9b9f-bf7ef68ebb4c.jpg)

????????????????????????????????ݴ?????

| ???? | ???? |
| -- | -- |
| :w | §Õ?????|
| :w! | ???????????????§Õ???????????????§Õ???????????????????§Û? |
| :q | ??|
| :q! | ???????????|
| :wq | §Õ????????|
| :wq!|  ???§Õ????????|


# ?¦Ï?????

- ???. ?? ?? ?? Linux ? ?? ?? ?? ?? ? ?? ?? ??[J]. 2009.
- [Linux ??????????????](https://www.ibm.com/developerworks/cn/linux/l-cn-rpmdpkg/index.html)