Shell三剑客：awk（格式化输出）
一、格式符
| %d |
十进制有符号整数 |
| %u |
十进制无符号整数 |
| %f |
浮点数 |
| %s |
字符串 |
| %c |
单个字符 |
| %p |
指针的值 |
| %e |
指数形式的浮点数 |
| %x |
%X 无符号以十六进制表示的整数 |
| %o |
无符号以八进制表示的整数 |
| %g |
自动选择合适的表示法 |
| % |
% 显示%自身 |
| # |
[.#] 第一个数字控制显示的宽度；第二个#表示小数点后精度，%3.1f |
| - |
左对齐（默认右对齐）；%-15s，就是以左对齐方式显示15个字符长度 |
| + |
显示数值的正负符号 %+d |
二、区别
- printf 时默认是不会换行的
- print 函数默认会在每行后面加上 \n 换行符
print函数：
[root@localhost ~]# awk '{print "hello,awk"}'
hello,awk
hello,awk
;
hello,awk
^C
[root@localhost ~]# awk -F: '{print}' passwd.txt
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/nologin10
[root@localhost ~]# awk -F: '{print "root"}' passwd.txt
root
root
root
root
root
root
root
root
root
root
[root@localhost ~]# awk -F: '{print $1}' passwd.txt
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
operator
[root@localhost ~]# awk -F: '{print $0}' passwd.txt
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/nologin10
[root@localhost ~]# awk -F: '{print $1"\t"$3}' passwd.txt
root 0
bin 1
daemon 2
adm 3
lp 4
sync 5
shutdown 6
halt 7
mail 8
operator 11
[root@localhost ~]# data | awk '{print "Month: "$2"\nYear:"$NF}'
-bash: data: 未找到命令
[root@localhost ~]# date | awk '{print "Month: "$2"\nYear:"$NF}'
Month: 12月
Year:CST
[root@localhost ~]# awk -F: '{print "username is: " $1 "\t uid is: " $3}' passwd.txt
username is: root uid is: 0
username is: bin uid is: 1
username is: daemon uid is: 2
username is: adm uid is: 3
username is: lp uid is: 4
username is: sync uid is: 5
username is: shutdown uid is: 6
username is: halt uid is: 7
username is: mail uid is: 8
username is: operator uid is: 11
[root@localhost ~]# awk -F: '{print "\tusername and uid: " $1,$3 "!"}'
username and uid: !
username and uid: !
username and uid: !
username and uid: !
^C
[root@localhost ~]# tail -3 passwd.txt | awk '{print $1,$3}'
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/nologin10
printf函数：
[root@localhost ~]# awk -F: '{printf "%-15s %-10s %-15s\n", $1,$2,$3}' passwd.txt
root x 0
bin x 1
daemon x 2
adm x 3
lp x 4
sync x 5
shutdown x 6
halt x 7
mail x 8
operator x 11
[root@localhost ~]# awk -F: '{printf "|%-15s| |%-10s| |%-15s|\n", $1,$2,$3}' passwd.txt
|root | |x | |0 |
|bin | |x | |1 |
|daemon | |x | |2 |
|adm | |x | |3 |
|lp | |x | |4 |
|sync | |x | |5 |
|shutdown | |x | |6 |
|halt | |x | |7 |
|mail | |x | |8 |
|operator | |x | |11 |
[root@localhost ~]# awk -F: '{printf "%s\n",$1}' passwd.txt
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
operator
[root@localhost ~]# awk -F: '{printf "%-20s %10d\n", $1,$3}' passwd.txt
root 0
bin 1
daemon 2
adm 3
lp 4
sync 5
shutdown 6
halt 7
mail 8
operator 11
[root@localhost ~]# awk -F: '{printf "username: %s\n", $1}' passwd.txt
username: root
username: bin
username: daemon
username: adm
username: lp
username: sync
username: shutdown
username: halt
username: mail
username: operator
[root@localhost ~]# awk -F: '{printf "username: %s,UID: %d\n", $1,$3}' passwd.txt
username: root,UID: 0
username: bin,UID: 1
username: daemon,UID: 2
username: adm,UID: 3
username: lp,UID: 4
username: sync,UID: 5
username: shutdown,UID: 6
username: halt,UID: 7
username: mail,UID: 8
username: operator,UID: 11
[root@localhost ~]# awk -F: '{printf "username: %15s,UID: %d\n", $1,$3}' passwd.txt
username: root,UID: 0
username: bin,UID: 1
username: daemon,UID: 2
username: adm,UID: 3
username: lp,UID: 4
username: sync,UID: 5
username: shutdown,UID: 6
username: halt,UID: 7
username: mail,UID: 8
username: operator,UID: 11
[root@localhost ~]# awk -F: '{printf "username: %-15s,UID: %d\n", $1,$3}' passwd.txt
username: root ,UID: 0
username: bin ,UID: 1
username: daemon ,UID: 2
username: adm ,UID: 3
username: lp ,UID: 4
username: sync ,UID: 5
username: shutdown ,UID: 6
username: halt ,UID: 7
username: mail ,UID: 8
username: operator ,UID: 11
[root@localhost ~]# lsmod | awk -v FS=" " 'BEGIN{printf "%s %26s %10s\n","Mo
dule","Size","Used by"}{printf "%-20s %13d %5s %s\n",$1,$2,$3,$4}' /proc/modules
Module Size Used by
ip6t_rpfilter 12595 1 -
ip6t_REJECT 12625 2 -
nf_reject_ipv6 13717 1 ip6t_REJECT,
ipt_REJECT 12541 2 -
nf_reject_ipv4 13373 1 ipt_REJECT,
xt_conntrack 12760 11 -
ebtable_nat 12807 1 -
ebtable_broute 12731 1 -
bridge 151336 1 ebtable_broute,
stp 12976 1 bridge,
llc 14552 2 bridge,stp,
ip6table_nat 12864 1 -
nf_conntrack_ipv6 18935 7 -
nf_defrag_ipv6 35104 1 nf_conntrack_ipv6,
nf_nat_ipv6 14131 1 ip6table_nat,
ip6table_mangle 12700 1 -
ip6table_security 12710 1 -
ip6table_raw 12683 1 -
iptable_nat 12875 1 -
nf_conntrack_ipv4 15053 6 -
nf_defrag_ipv4 12729 1 nf_conntrack_ipv4,
nf_nat_ipv4 14115 1 iptable_nat,
nf_nat 26583 2 nf_nat_ipv6,nf_nat_ipv4,
iptable_mangle 12695 1 -
iptable_security 12705 1 -
iptable_raw 12678 1 -
nf_conntrack 139264 6 xt_conntrack,nf_conntrack_ipv6,nf_nat_ipv6,nf_conntrack_ipv4,nf_nat_ipv4,nf_nat,
ip_set 45799 0 -
nfnetlink 14519 1 ip_set,
ebtable_filter 12827 1 -
ebtables 35009 3 ebtable_nat,ebtable_broute,ebtable_filter,
ip6table_filter 12815 1 -
ip6_tables 26912 5 ip6table_nat,ip6table_mangle,ip6table_security,ip6table_raw,ip6table_filter,
iptable_filter 12810 1 -
vmw_vsock_vmci_transport 30577 1 -
vsock 36367 2 vmw_vsock_vmci_transport,
iosf_mbi 15582 0 -
crc32_pclmul 13133 0 -
ppdev 17671 0 -
ghash_clmulni_intel 13273 0 -
btusb 41520 0 -
btrtl 12945 1 btusb,
btbcm 14040 1 btusb,
btintel 15709 1 btusb,
aesni_intel 189456 0 -
lrw 13286 1 aesni_intel,
gf128mul 15139 1 lrw,
bluetooth 548688 5 btusb,btrtl,btbcm,btintel,
vmw_balloon 18094 0 -
glue_helper 13990 1 aesni_intel,
ablk_helper 13597 1 aesni_intel,
cryptd 21190 3 ghash_clmulni_intel,aesni_intel,ablk_helper,
pcspkr 12718 0 -
joydev 17389 0 -
sg 40719 0 -
rfkill 22391 1 bluetooth,
vmw_vmci 67168 1 vmw_vsock_vmci_transport,
i2c_piix4 22401 0 -
parport_pc 28205 0 -
parport 46395 2 ppdev,parport_pc,
ip_tables 27126 5 iptable_nat,iptable_mangle,iptable_security,iptable_raw,iptable_filter,
xfs 997727 2 -
libcrc32c 12644 3 nf_nat,nf_conntrack,xfs,
sr_mod 22416 0 -
cdrom 42600 1 sr_mod,
ata_generic 12923 0 -
pata_acpi 13053 0 -
vmwgfx 291993 1 -
sd_mod 46281 3 -
crc_t10dif 12912 1 sd_mod,
crct10dif_generic 12647 0 -
drm_kms_helper 186531 1 vmwgfx,
syscopyarea 12529 1 drm_kms_helper,
sysfillrect 12701 1 drm_kms_helper,
sysimgblt 12640 1 drm_kms_helper,
fb_sys_fops 12703 1 drm_kms_helper,
ttm 96673 1 vmwgfx,
crct10dif_pclmul 14307 1 -
crct10dif_common 12595 3 crc_t10dif,crct10dif_generic,crct10dif_pclmul,
crc32c_intel 22094 1 -
drm 456166 4 vmwgfx,drm_kms_helper,ttm,
ata_piix 35052 0 -
mptspi 22673 2 -
e1000 137624 0 -
nfit 55639 0 -
libata 243094 3 ata_generic,pata_acpi,ata_piix,
scsi_transport_spi 30732 1 mptspi,
serio_raw 13434 0 -
mptscsih 40150 1 mptspi,
libnvdimm 159524 1 nfit,
mptbase 106036 2 mptspi,mptscsih,
drm_panel_orientation_quirks 17180 1 drm,
dm_mirror 22289 0 -
dm_region_hash 20813 1 dm_mirror,
dm_log 18411 2 dm_mirror,dm_region_hash,
dm_mod 124501 8 dm_mirror,dm_log,
fuse 100350 1 -
