cut [选项] 文件名
选项：
-f 列号：提取第几列
-d 分隔符：按照指定分隔符分割列

[root@localhost ~]# cat student.txt
1 furong F 85
2 fengj F 60
3 cang F 70
[root@localhost ~]# cut -f 2 student.txt
furong
fengj
cang
[root@localhost ~]# cut -f 2,4 student.txt
furong 85
fengj 60
cang 70
[root@localhost ~]# grep "/bin/bash" /etc/passwd|grep -v "root"|cut -f 1 -d ":"
cakin24
test
cls
[root@localhost ~]# cut -d ":" -f 1,3 /etc/passwd
root:0
bin:1
daemon:2
adm:3
lp:4
sync:5
shutdown:6
halt:7
mail:8
operator:11
games:12
ftp:14
nobody:99
systemd-bus-proxy:999
systemd-network:998
dbus:81
polkitd:997
abrt:173
unbound:996
tss:59
colord:995
usbmuxd:113
geoclue:994
rpc:32
rtkit:172
chrony:993
radvd:75
qemu:107
avahi-autoipd:170
setroubleshoot:992
rpcuser:29
nfsnobody:65534
saslauth:991
libstoragemgmt:990
pulse:171
gdm:42
gnome-initial-setup:989
avahi:70
sshd:74
postfix:89
ntp:38
tcpdump:72
cakin24:1000
test:1003
cls:1001

df -h|cut -d " " -f 1,3