字符截取:cut,格式化输出:printf,字符截取:awk,文件或命令输出编辑:sed

cut 选项 文件名

-f 列号  提取第几列

-d 分隔符  指定分隔符把行分成多列

不能以空格为分隔符。

[root@localhost ~]# cat testfile
no.     name    sex     score
1       zhangsan        m       88
2       lisi    f       89
3       wangwu  m       87
[root@localhost ~]# cut -f 2 testfile  注释:默认分隔符是制表符	
name
zhangsan
lisi
wangwu
[root@localhost ~]# cut -f 2,4 testfile
name    score
zhangsan        88
lisi    89
wangwu  87
[root@localhost ~]# cat testfile
no.     na:me   sex     sco:re
1       zhang:san       m       8:8
2       li:si   f       8:9
3       wang:wu m       8:7
[root@localhost ~]# cut -f 1,3 -d : testfile
no.     na:re
1       zhang:8
2       li:9
3       wang:7
root@localhost ~]# cut -f 1 -d : /etc/passwd|grep xiong
xiongjiawei
[root@localhost ~]# grep xiong /etc/passwd|cut -d : -f 1
xiongjiawei
[root@localhost ~]# grep xiong /etc/passwd|cut -d ":" -f 1
xiongjiawei
[root@localhost ~]# grep xiong /etc/passwd|cut -f 1 -d :
xiongjiawei
[root@localhost ~]# grep xiong /etc/passwd|cut -f 1 -d ":" 
xiongjiawei 

printf '格式' 输出内容

%ns  输出n个字符串

%ni  输出n个数字

%n.mf  输出共n位数字,m位小数,如%5.2f表示共3位整数,2位小数

a  警告声

  Backspace键

f  清屏

  换行,常用

  Enter,常用

  Tab,常用

v  垂直Tab

awk支持printf和print(linux默认无此命令),print输出会自动加换行,printf是标准格式输出命令,不会自动加换行,如果要换行需要手动加。

[root@localhost ~]# printf %s a b cd ef g 1 2
abcdefg12[root@localhost ~]# printf %s %s a b cd ef g 1 2  
%sabcdefg12[root@localhost ~]# printf '%s %s' a b cd ef g 1 2
a bcd efg 12 [root@localhost ~]# printf '%s
%s' a b cd ef g 1 2 
a
bcd
efg
12
[root@localhost ~]# printf '%s %s
' a b cd ef g 1 2  
a b
cd ef
g 1
2 
[root@localhost ~]# printf %s $(cat testfile)
no.na:mesexsco:re1zhang:sanm8:82li:sif8:93wang:wum8:7[root@localhost ~]# 
[root@localhost ~]# cat testfile
no.     na:me   sex     sco:re
1       zhang:san       m       8:8
2       li:si   f       8:9
3       wang:wu m       8:7

awk '条件1{动作1} 条件2{运行2}...' 文件名

默认以空格为分隔符,执行命令时首先读取文件一行。

[root@localhost ~]# cat testfile
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# awk {printf $2 $4} testfile
awk: cmd. line:1: {printf
awk: cmd. line:1:        ^ unexpected newline or end of string  注释:报错的原因是awk命令后的条件动作未加单引号
[root@localhost ~]# awk '{printf $2 $4}' testfile
namescorezhansan88li:si89wangwu87[root@localhost ~]# awk '{printf $2	$4
}' testfile  
awk: cmd. line:1: {printf $2	$4
}
awk: cmd. line:1:           ^ backslash not last character on line
awk: cmd. line:1: {printf $2	$4
}
awk: cmd. line:1:           ^ syntax error  注释:报错是因为制表符	未加双引号
[root@localhost ~]# awk '{printf $2 "	" $4 
}' testfile
awk: cmd. line:1: {printf $2 "	" $4 
}
awk: cmd. line:1:                    ^ backslash not last character on line
awk: cmd. line:1: {printf $2 "	" $4 
}
awk: cmd. line:1:                    ^ syntax error  注释:报错是因为换行符
未加双引号
[root@localhost ~]# awk '{printf $2 "	" $4 "
"}' testfile
name    score
zhansan 88
li:si   89
wangwu  87
[root@localhost ~]# awk '{printf $2"	"$4"
"}' testfile   
name    score
zhansan 88
li:si   89
wangwu  87
[root@localhost ~]# df -h|awk '{printf $1}'
文件系统/dev/sda5devtmpfstmpfstmpfstmpfs/dev/sda2/dev/sdb5/dev/sdb1/dev/sda1tmpfs[root@localhost ~]# df -h|awk '{printf $1"
"}'
文件系统
/dev/sda5
devtmpfs
tmpfs
tmpfs
tmpfs
/dev/sda2
/dev/sdb5
/dev/sdb1
/dev/sda1
tmpfs
[root@localhost ~]# df -h|awk '{print $1}'     
文件系统
/dev/sda5
devtmpfs
tmpfs
tmpfs
tmpfs
/dev/sda2
/dev/sdb5
/dev/sdb1
/dev/sda1
tmpfs
[root@localhost ~]# df
文件系统          1K-块    已用     可用 已用% 挂载点
/dev/sda5      16558080 1443112 15114968    9% /
devtmpfs         490168       0   490168    0% /dev
tmpfs            499968       0   499968    0% /dev/shm
tmpfs            499968    6872   493096    2% /run
tmpfs            499968       0   499968    0% /sys/fs/cgroup
/dev/sda2       2086912   33160  2053752    2% /home
/dev/sdb5       1998672    6144  1871288    1% /disk5
/dev/sdb1        999320    2564   927944    1% /disk1
/dev/sda1        201380  116576    84804   58% /boot
tmpfs             99996       0    99996    0% /run/user/0
[root@localhost ~]# df -h|grep sda5
/dev/sda5        16G  1.4G   15G    9% /
[root@localhost ~]# df -h|grep sda5|awk '{print $5}'
9%
[root@localhost ~]# df -h|grep sda5|awk '{print $5}'|cut -d % -f1  注释:cut命令的-f选项后的列序号和f之间可以无空格
9
[root@localhost ~]# df -h|grep sda5|awk '{print $5}'|cut -d % -f 1
9
[root@localhost ~]# df -h|grep sda5|awk 'BEGIN{print "This is a title:"}{print $5}'|cut -d % -f 1              
This is a title:
9
[root@localhost ~]# df -h|grep sda5|awk '{print "This is a title:"}{print $5}'|cut -d % -f1      
This is a title:
9
[root@localhost ~]# awk '{print $1}' /etc/passwd  注释:awk的默认分隔符是空格
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-bus-proxy:x:999:997:systemd
systemd-network:x:192:192:systemd
dbus:x:81:81:System
polkitd:x:998:996:User
libstoragemgmt:x:997:995:daemon
abrt:x:173:173::/etc/abrt:/sbin/nologin
rpc:x:32:32:Rpcbind
tss:x:59:59:Account
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated
ntp:x:38:38::/etc/ntp:/sbin/nologin
chrony:x:996:994::/var/lib/chrony:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
xiongjiawei:x:1000:1000:xiongjiawei:/home/xiongjiawei:/bin/bash
qiaofeng:x:1001:1001::/home/qiaofeng:/bin/bash
yangguo:x:1002:1002::/home/yangguo:/bin/bash
st:x:1003:1004::/home/st:/bin/bash
user1:x:1004:1005::/home/user1:/bin/bash
[root@localhost ~]# awk '{FS=":"}{print $1}' /etc/passwd  
root:x:0:0:root:/root:/bin/bash  注释:设置分隔符为冒号:后第一行并未处理,因为awk命令的执行是首先读取第一行
bin
daemon
adm
lp
sync
shutdown
halt
mail
operator
games
ftp
nobody
systemd-bus-proxy
systemd-network
dbus
polkitd
libstoragemgmt
abrt
rpc
tss
postfix
sshd
ntp
chrony
tcpdump
xiongjiawei
qiaofeng
yangguo
st
user1
[root@localhost ~]# awk 'BEGIN{FS=":"}{print $1}' /etc/passwd   注释:加BEGIN后就不会首先读取第一行,而是首先设置分隔符
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
operator
games
ftp
nobody
systemd-bus-proxy
systemd-network
dbus
polkitd
libstoragemgmt
abrt
rpc
tss
postfix
sshd
ntp
chrony
tcpdump
xiongjiawei
qiaofeng
yangguo
st
user1
[root@localhost ~]# awk 'END{print "The end!"}BEGIN{FS=":"}{print $1}' /etc/passwd        注释:有BEGIN就有END,在命令动作中的顺序无所谓              
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
operator
games
ftp
nobody
systemd-bus-proxy
systemd-network
dbus
polkitd
libstoragemgmt
abrt
rpc
tss
postfix
sshd
ntp
chrony
tcpdump
xiongjiawei
qiaofeng
yangguo
st
user1
The end!
[root@localhost ~]# cat testfile
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# awk '$4>88{print $2}' testfile  注释:根据条件执行动作
name
li:si

sed

 sed [选项] '[动作]' 文件名

选项:

-n 只输出sed处理过的行

-i 修改原文件

-e 执行多条sed动作

动作:

p 打印,例2p打印第2行,2,3p打印第2、3行

d 删除,例‘3,4d',不输出第3、4行

a 追加,例'2a Welcome to China',在第2行后换行追加Welcom to China

i 插入,例'2i Welcom to China',在第2行前插入Welcom to China,即在第1行后换行插入Welcom to China

c 行替换

s 字符串替换

[root@localhost ~]# cat testfile
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# sed '2p' testfile  注释:不加选项-n时即输出原文件又输出经过处理的结果
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
1       zhansan m       88      18      student
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# sed -n '2p' testfile
1       zhansan m       88      18      student
[root@localhost ~]# sed -n '2,3p' testfile
1       zhansan m       88      18      student
2       li:si   f       89      20      member
[root@localhost ~]# df -h|sed -n '2p'
/dev/sda5        16G  1.4G   15G    9% /
[root@localhost ~]# sed '3,4d' testfile
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
[root@localhost ~]# df -h|sed '2a This is added words'
文件系统        容量  已用  可用 已用% 挂载点
/dev/sda5        16G  1.4G   15G    9% /
This is added words
devtmpfs        479M     0  479M    0% /dev
tmpfs           489M     0  489M    0% /dev/shm
tmpfs           489M  6.8M  482M    2% /run
tmpfs           489M     0  489M    0% /sys/fs/cgroup
/dev/sda2       2.0G   33M  2.0G    2% /home
/dev/sdb5       2.0G  6.0M  1.8G    1% /disk5
/dev/sdb1       976M  2.6M  907M    1% /disk1
/dev/sda1       197M  114M   83M   58% /boot
tmpfs            98M     0   98M    0% /run/user/0
[root@localhost ~]# df -h|sed '2i This is added words' 
文件系统        容量  已用  可用 已用% 挂载点
This is added words
/dev/sda5        16G  1.4G   15G    9% /
devtmpfs        479M     0  479M    0% /dev
tmpfs           489M     0  489M    0% /dev/shm
tmpfs           489M  6.8M  482M    2% /run
tmpfs           489M     0  489M    0% /sys/fs/cgroup
/dev/sda2       2.0G   33M  2.0G    2% /home
/dev/sdb5       2.0G  6.0M  1.8G    1% /disk5
/dev/sdb1       976M  2.6M  907M    1% /disk1
/dev/sda1       197M  114M   83M   58% /boot
tmpfs            98M     0   98M    0% /run/user/0
[root@localhost ~]# df -h|sed '2i This is added words'
文件系统        容量  已用  可用 已用% 挂载点
This is dded words
/dev/sda5        16G  1.4G   15G    9% /
devtmpfs        479M     0  479M    0% /dev
tmpfs           489M     0  489M    0% /dev/shm
tmpfs           489M  6.8M  482M    2% /run
tmpfs           489M     0  489M    0% /sys/fs/cgroup
/dev/sda2       2.0G   33M  2.0G    2% /home
/dev/sdb5       2.0G  6.0M  1.8G    1% /disk5
/dev/sdb1       976M  2.6M  907M    1% /disk1
/dev/sda1       197M  114M   83M   58% /boot
tmpfs            98M     0   98M    0% /run/user/0
[root@localhost ~]# df -h|sed '2i This is 
> added words' 
文件系统        容量  已用  可用 已用% 挂载点
This is 
added words
/dev/sda5        16G  1.4G   15G    9% /
devtmpfs        479M     0  479M    0% /dev
tmpfs           489M     0  489M    0% /dev/shm
tmpfs           489M  6.8M  482M    2% /run
tmpfs           489M     0  489M    0% /sys/fs/cgroup
/dev/sda2       2.0G   33M  2.0G    2% /home
/dev/sdb5       2.0G  6.0M  1.8G    1% /disk5
/dev/sdb1       976M  2.6M  907M    1% /disk1
/dev/sda1       197M  114M   83M   58% /boot
tmpfs            98M     0   98M    0% /run/user/0
[root@localhost ~]# sed '2c deleted...' testfile
no.     name    sex     score   age     comment
deleted...
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# sed '2c deleted...
> new lines!!!' testfile
no.     name    sex     score   age     comment
deleted...
new lines!!!
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# cat testfile
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher

[root@localhost ~]# sed '3s/li:si/lisi/g' testfile   注释:2表示行序号,不加数字表示替换整个文档
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
2       lisi    f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# cat testfile
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
2       li:si   f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# sed -i '3s/li:si/lisi/g' testfile  注释:-i选项表示修改原文件,此选项有一定风险性,慎用,如果需要修改文件内容建议使用vim
[root@localhost ~]# cat testfile                     
no.     name    sex     score   age     comment
1       zhansan m       88      18      student
2       lisi    f       89      20      member
3       wangwu  m       87      22      teacher
[root@localhost ~]# sed -e '2s/zhansan/sanzhan/g;3s/li/Li/g' testfile
no.     name    sex     score   age     comment
1       sanzhan m       88      18      student
2       Lisi    f       89      20      member
3       wangwu  m       87      22      teacher
原文地址:https://www.cnblogs.com/xiongjiawei/p/7353639.html