显示/etc 目录下，以非字母开头，后面跟了一个字母以及其它任意长度任意字符的文件或目录。

[root@localhost ~]# ls /etc/
abrt                       chromium                    ethertypes    gss            libblockdev               networks           profile.d         scl                 target
adjtime                    chrony.conf                 exports       gssproxy       libibverbs.d              nfs.conf           protocols         securetty           tcsd.conf
aliases                    chrony.keys                 exports.d     host.conf      libnl                     nfsmount.conf      pulse             security            terminfo
aliases.db                 cifs-utils                  favicon.png   hostname       libpaper.d                nsswitch.conf      purple            selinux             tmpfiles.d
alsa                       cron.d                      fcoe          hosts          libreport                 nsswitch.conf.bak  python            services            trusted-key.key
alternatives               cron.daily                  festival      hosts.allow    libuser.conf              ntp                qemu-ga           sestatus.conf       tuned
anacrontab                 cron.deny                   filesystems   hosts.deny     libvirt                   ntp.conf           qemu-kvm          setroubleshoot      udev
asound.conf                cron.hourly                 firefox       hp             locale.conf               numad.conf         radvd.conf        setuptool.d         udisks2
at.deny                    cron.monthly                firewalld     idmapd.conf    localtime                 oddjob             rc0.d             sgml                unbound
audisp                     crontab                     flatpak       init.d         login.defs                oddjobd.conf       rc1.d             shadow              updatedb.conf
audit                      cron.weekly                 fonts         inittab        logrotate.conf            oddjobd.conf.d     rc2.d             shadow-             UPower
autofs.conf                crypttab                    fprintd.conf  inputrc        logrotate.d               openldap           rc3.d             shells              usb_modeswitch.conf
autofs_ldap_auth.conf      csh.cshrc                   fstab         ipa            lsm                       opt                rc4.d             skel                vconsole.conf
auto.master                csh.login                   fuse.conf     iproute2       lvm                       os-release         rc5.d             smartmontools       vimrc
auto.master.d              cups                        fwupd         ipsec.conf     machine-id                PackageKit         rc6.d             sos.conf            virc
auto.misc                  cupshelpers                 gconf         ipsec.d        magic                     pam.d              rc.d              speech-dispatcher   vmware-tools
auto.net                   dbus-1                      gcrypt        ipsec.secrets  mail.rc                   papersize          rc.local          ssh                 wgetrc
auto.smb                   dconf                       gdbinit       iscsi          makedumpfile.conf.sample  passwd             rdma              ssl                 wpa_supplicant
avahi                      default                     gdbinit.d     issue          man_db.conf               passwd-            redhat-release    sssd                wvdial.conf
bash_completion.d          depmod.d                    gdm           issue.net      maven                     pbm2ppa.conf       request-key.conf  statetab            X11
bashrc                     dhcp                        geoclue       issue.out      mke2fs.conf               pinforc            request-key.d     statetab.d          xdg
binfmt.d                   DIR_COLORS                  GeoIP.conf    java           modprobe.d                pkcs11             resolv.conf       subgid              xinetd.d
bluetooth                  DIR_COLORS.256color         ghostscript   jvm            modules-load.d            pki                resolv.conf.save  subuid              xml
brltty                     DIR_COLORS.lightbgcolor     glvnd         jvm-commmon    motd                      plymouth           rpc               sudo.conf           yum
brltty.conf                dleyna-server-service.conf  gnupg         kdump.conf     mtab                      pm                 rpm               sudoers             yum.conf
centos-release             dnsmasq.conf                GREP_COLORS   kernel         mtools.conf               pnm2ppa.conf       rsyncd.conf       sudoers.d           yum.repos.d
centos-release-upstream    dnsmasq.d                   groff         krb5.conf      multipath                 polkit-1           rsyslog.conf      sudo-ldap.conf
certmonger                 dracut.conf                 group         krb5.conf.d    my.cnf                    popt.d             rsyslog.d         sysconfig
cgconfig.conf              dracut.conf.d               group-        ksmtuned.conf  my.cnf.d                  postfix            rwtab             sysctl.conf
cgconfig.d                 e2fsck.conf                 grub2.cfg     ld.so.cache    nanorc                    ppp                rwtab.d           sysctl.d
cgrules.conf               egl                         grub.d        ld.so.conf     ndctl                     prelink.conf.d     samba             systemd
cgsnapshot_blacklist.conf  enscript.cfg                gshadow       ld.so.conf.d   netconfig                 printcap           sane.d            system-release
chkconfig.d                environment                 gshadow-      libaudit.conf  NetworkManager            profile            sasl2             system-release-cpe
[root@localhost ~]# touch /etc/1a232123sdf
[root@localhost ~]# mkdir /etc/2c3234
[root@localhost ~]# mkdir /etc/2bsdfs2342342323
[root@localhost ~]# ls -d /etc/[^[:alpha:]][:alpha:]*
/etc/1a232123sdf
[root@localhost ~]# ls -a  /etc/[^[:alpha:]][[:alpha:]]* 
/etc/1a232123sdf

/etc/2bsdfs2342342323:
.  ..

/etc/2c3234:
.  ..
[root@localhost ~]# ls /etc/
1a232123sdf              cgrules.conf                egl           grub.d         ld.so.conf                ndctl              prelink.conf.d    samba              systemd
2bsdfs2342342323         cgsnapshot_blacklist.conf   enscript.cfg  gshadow        ld.so.conf.d              netconfig          printcap          sane.d             system-release
2c3234                   chkconfig.d                 environment   gshadow-       libaudit.conf             NetworkManager     profile           sasl2              system-release-cpe
abrt                     chromium                    ethertypes    gss            libblockdev               networks           profile.d         scl                target
adjtime                  chrony.conf                 exports       gssproxy       libibverbs.d              nfs.conf           protocols         securetty          tcsd.conf
aliases                  chrony.keys                 exports.d     host.conf      libnl                     nfsmount.conf      pulse             security           terminfo
aliases.db               cifs-utils                  favicon.png   hostname       libpaper.d                nsswitch.conf      purple            selinux            tmpfiles.d
alsa                     cron.d                      fcoe          hosts          libreport                 nsswitch.conf.bak  python            services           trusted-key.key
alternatives             cron.daily                  festival      hosts.allow    libuser.conf              ntp                qemu-ga           sestatus.conf      tuned
anacrontab               cron.deny                   filesystems   hosts.deny     libvirt                   ntp.conf           qemu-kvm          setroubleshoot     udev
asound.conf              cron.hourly                 firefox       hp             locale.conf               numad.conf         radvd.conf        setuptool.d        udisks2
at.deny                  cron.monthly                firewalld     idmapd.conf    localtime                 oddjob             rc0.d             sgml               unbound
audisp                   crontab                     flatpak       init.d         login.defs                oddjobd.conf       rc1.d             shadow             updatedb.conf
audit                    cron.weekly                 fonts         inittab        logrotate.conf            oddjobd.conf.d     rc2.d             shadow-            UPower
autofs.conf              crypttab                    fprintd.conf  inputrc        logrotate.d               openldap           rc3.d             shells             usb_modeswitch.conf
autofs_ldap_auth.conf    csh.cshrc                   fstab         ipa            lsm                       opt                rc4.d             skel               vconsole.conf
auto.master              csh.login                   fuse.conf     iproute2       lvm                       os-release         rc5.d             smartmontools      vimrc
auto.master.d            cups                        fwupd         ipsec.conf     machine-id                PackageKit         rc6.d             sos.conf           virc
auto.misc                cupshelpers                 gconf         ipsec.d        magic                     pam.d              rc.d              speech-dispatcher  vmware-tools
auto.net                 dbus-1                      gcrypt        ipsec.secrets  mail.rc                   papersize          rc.local          ssh                wgetrc
auto.smb                 dconf                       gdbinit       iscsi          makedumpfile.conf.sample  passwd             rdma              ssl                wpa_supplicant
avahi                    default                     gdbinit.d     issue          man_db.conf               passwd-            redhat-release    sssd               wvdial.conf
bash_completion.d        depmod.d                    gdm           issue.net      maven                     pbm2ppa.conf       request-key.conf  statetab           X11
bashrc                   dhcp                        geoclue       issue.out      mke2fs.conf               pinforc            request-key.d     statetab.d         xdg
binfmt.d                 DIR_COLORS                  GeoIP.conf    java           modprobe.d                pkcs11             resolv.conf       subgid             xinetd.d
bluetooth                DIR_COLORS.256color         ghostscript   jvm            modules-load.d            pki                resolv.conf.save  subuid             xml
brltty                   DIR_COLORS.lightbgcolor     glvnd         jvm-commmon    motd                      plymouth           rpc               sudo.conf          yum
brltty.conf              dleyna-server-service.conf  gnupg         kdump.conf     mtab                      pm                 rpm               sudoers            yum.conf
centos-release           dnsmasq.conf                GREP_COLORS   kernel         mtools.conf               pnm2ppa.conf       rsyncd.conf       sudoers.d          yum.repos.d
centos-release-upstream  dnsmasq.d                   groff         krb5.conf      multipath                 polkit-1           rsyslog.conf      sudo-ldap.conf
certmonger               dracut.conf                 group         krb5.conf.d    my.cnf                    popt.d             rsyslog.d         sysconfig
cgconfig.conf            dracut.conf.d               group-        ksmtuned.conf  my.cnf.d                  postfix            rwtab             sysctl.conf
cgconfig.d               e2fsck.conf                 grub2.cfg     ld.so.cache    nanorc                    ppp                rwtab.d           sysctl.d
[root@localhost ~]# 

---

复制/etc 目录下所有以p开头，以非数字结尾的文件或目录到/tmp/mytest1目录中。

[root@localhost ~]# mkdir /tmp/mytest{1..3}
[root@localhost ~]# cp -a /etc/p*[^[:digit:]] /tmp/mytest1/
[root@localhost ~]# ls /tmp/mytest1
pam.d      passwd   pbm2ppa.conf  pki       pm            popt.d   ppp             printcap  profile.d  pulse   python
papersize  passwd-  pinforc       plymouth  pnm2ppa.conf  postfix  prelink.conf.d  profile   protocols  purple

[root@localhost ~]# cp -a /etc/p*[^0-9] /tmp/mytest2/
[root@localhost ~]# ls /tmp/mytest2
pam.d      passwd   pbm2ppa.conf  pki       pm            popt.d   ppp             printcap  profile.d  pulse   python
papersize  passwd-  pinforc       plymouth  pnm2ppa.conf  postfix  prelink.conf.d  profile   protocols  purple

[root@localhost ~]# cp -a /etc/p*[a-Z] /tmp/mytest3/
[root@localhost ~]# ls /tmp/mytest3
pam.d  papersize  passwd  pbm2ppa.conf  pinforc  pki  plymouth  pm  pnm2ppa.conf  popt.d  postfix  ppp  prelink.conf.d  printcap  profile  profile.d  protocols  pulse  purple  python
这种是不正确的方式，与题目不太相符。

---

将/etc/issue文件中的内容转换为大写后保存至/tmp/issue.out 文件中。

[root@localhost ~]# cat /etc/issue
\S
Kernel \r on an \m

[root@localhost ~]# tr [:lower:] [:upper:] < /etc/issue > /etc/issue.out
[root@localhost ~]# 
[root@localhost ~]# cat /etc/issue.out 
\S
KERNEL \R ON AN \M

[root@localhost ~]# cat /etc/issue
\S
Kernel \r on an \m

[root@localhost ~]#

[root@localhost abc]# cat /etc/issue | tr 'a-z' 'A-Z' > /etc/issue.out
[root@localhost abc]# cat /etc/issue
\S
Kernel \r on an \m

[root@localhost abc]# 
[root@localhost abc]# cat /etc/issue.out
\S
KERNEL \R ON AN \M

---

总结描述用户和组管理类命令的使用方法并完成一下练习。
创建组 distro ，其GID为 2019 ；

[root@localhost abc]# getent group distro
[root@localhost abc]# groupadd distro -g 2019
[root@localhost abc]# getent group distro
distro:x:2019:
[root@localhost abc]# 

创建用户 mandriva ，其ID号为 1005 ，基本组为 distro ；

[root@localhost abc]# useradd mandriva -u 1005 -g distro
[root@localhost abc]# id mandriva
uid=1005(mandriva) gid=2019(distro) groups=2019(distro)
[root@localhost abc]# 

创建用户 mageia ，其ID号为 1100，家目录为 /home/linux ；

[root@localhost abc]# useradd mageia -u 1100 -d /home/linux -m
[root@localhost abc]# ls /home/
edward  linux  mandriva
[root@localhost abc]# id mageia
uid=1100(mageia) gid=1100(mageia) groups=1100(mageia)
[root@localhost abc]# getent passwd mageia
mageia:x:1100:1100::/home/linux:/bin/bash
[root@localhost abc]# 

给用户mageia 添加密码，密码为 mageedu ，并设置用户密码7天后过期；

[root@localhost abc]# echo mageia:mageedu | chpasswd
[root@localhost abc]# chage -l mageia
Last password change					: May 03, 2020
Password expires					: never
Password inactive					: never
Account expires						: never
Minimum number of days between password change		: 0
Maximum number of days between password change		: 99999
Number of days of warning before password expires	: 7
[root@localhost abc]# chage -M 7 mageia
[root@localhost abc]# chage -l mageia
Last password change					: May 03, 2020
Password expires					: May 10, 2020
Password inactive					: never
Account expires						: never
Minimum number of days between password change		: 0
Maximum number of days between password change		: 7
Number of days of warning before password expires	: 7
[root@localhost abc]# date -s '10 day'
Thu May 14 05:46:44 CST 2020
[root@localhost abc]# su - edward
Last login: Mon May  4 05:44:36 CST 2020 on pts/1
[edward@localhost ~]$ su - mageia
Password: 
You are required to change your password immediately (password aged)
Changing password for mageia.
(current) UNIX password: 
New password: 
Retype new password: 
Last login: Thu May 14 05:46:52 CST 2020 on pts/1
Last failed login: Thu May 14 05:47:44 CST 2020 on pts/1
There was 1 failed login attempt since the last successful login.
[mageia@localhost ~]$ id
uid=1100(mageia) gid=1100(mageia) groups=1100(mageia)

删除 mandriva ，但保留其家目录；

[root@localhost abc]# userdel mandriva
[root@localhost abc]# ls /home/mandriva/
test
[root@localhost abc]# ls /home/
edward  linux  mandriva  slackware  test1  test2  test3  test4
[root@localhost abc]# 

创建用户 slackware ，其ID号为 2002 ，基本组为 distro ，附加组 peguin ；

[root@localhost abc]# groupadd peguin
[root@localhost abc]# useradd slackware -u 2002 -g distro -G peguin
[root@localhost abc]# id slackware
uid=2002(slackware) gid=2019(distro) groups=2019(distro),2020(peguin)
[root@localhost abc]# 

修改 slackware 的默认shell为 /bin/tcsh ；

[root@localhost abc]# clear
[root@localhost abc]# getent passwd slackware
slackware:x:2002:2019:slackware name,depops,123,456:/home/slackware:/bin/bash
[root@localhost abc]# chsh -s /bin/tcsh slackware
Changing shell for slackware.
Shell changed.
[root@localhost abc]# getent passwd slackware
slackware:x:2002:2019:slackware name,depops,123,456:/home/slackware:/bin/tcsh
[root@localhost abc]# chsh -s /bin/bash slackware
Changing shell for slackware.
Shell changed.
[root@localhost abc]# getent passwd slackware
slackware:x:2002:2019:slackware name,depops,123,456:/home/slackware:/bin/bash
[root@localhost abc]# usermod -s /bin/tcsh slackware
[root@localhost abc]# getent passwd slackware
slackware:x:2002:2019:slackware name,depops,123,456:/home/slackware:/bin/tcsh
[root@localhost abc]# 

为用户 slackware 新增附加组 admins；

[root@localhost abc]# id slackware
uid=2002(slackware) gid=2019(distro) groups=2019(distro),2020(peguin)
[root@localhost abc]# groupadd admins
[root@localhost abc]# usermod -aG admins slackware
[root@localhost abc]# id slackware
uid=2002(slackware) gid=2019(distro) groups=2019(distro),2020(peguin),2021(admins)

---

命令随笔：

[root@localhost abc]# hostname |tr 'a-z' 'A-Z'
LOCALHOST.LOCALDOMAIN
[root@localhost abc]# hos |tr 'a-z' 'A-Z'
bash: hos: command not found...
[root@localhost abc]# hos 2>&1 |tr 'a-z' 'A-Z'
BASH: HOS: COMMAND NOT FOUND...
[root@localhost abc]# hos |& tr 'a-z' 'A-Z'
BASH: HOS: COMMAND NOT FOUND...
[root@localhost abc]#

[root@localhost abc]# echo magedu | passwd --stdin edward
Changing password for user edward.
passwd: all authentication tokens updated successfully.
[root@localhost abc]# echo magedu | passwd --stdin edward > /dev/null

[root@localhost abc]# cat edward.file
cat: edward.file: No such file or directory
[root@localhost abc]# cat edward.file > test1.log  2> test2.log
[root@localhost abc]# ls
test1.log  test2.log
[root@localhost abc]# cat test1.log 
[root@localhost abc]# cat test2.log 
cat: edward.file: No such file or directory
[root@localhost abc]# 
[root@localhost abc]# cat edward.file &> test3.log
[root@localhost abc]# cat test3.log 
cat: edward.file: No such file or directory
[root@localhost abc]# cat edward.file > test4.log 2>&1
[root@localhost abc]# cat test4.log 
cat: edward.file: No such file or directory

[root@localhost abc]# hostname | tee /tmp/abc/test1
localhost.localdomain
[root@localhost abc]# cat test1 
localhost.localdomain
[root@localhost abc]# 
[root@localhost abc]# uname -r  | tee /tmp/abc/test1
3.10.0-1062.el7.x86_64
[root@localhost abc]# cat test1 
3.10.0-1062.el7.x86_64
[root@localhost abc]# 
[root@localhost abc]# hostname | tee  -a /tmp/abc/test1
localhost.localdomain
[root@localhost abc]# 
[root@localhost abc]# cat test1 
3.10.0-1062.el7.x86_64
localhost.localdomain
[root@localhost abc]# 
[root@localhost abc]# 
[root@localhost abc]# hostname | tee  -a /tmp/abc/test1 |tr 'a-z' 'A-Z'
LOCALHOST.LOCALDOMAIN
[root@localhost abc]# cat test1 
3.10.0-1062.el7.x86_64
localhost.localdomain
localhost.localdomain

[root@localhost abc]# su - edward
[edward@localhost ~]$ mail -s help root < I am $USER . please help me.
> `cat /etc/issue` 
> EOF
[edward@localhost ~]$ exit
logout
[root@localhost abc]# mail
Heirloom Mail version 12.5 7/5/10.  Type ? for help.
"/var/spool/mail/root": 1 message 1 new
>N  1 edward                Mon May  4 02:26  20/662   "help"
& 1
Message  1:
From edward@localhost.localdomain  Mon May  4 02:26:14 2020
Return-Path: 
X-Original-To: root
Delivered-To: root@localhost.localdomain
Date: Mon, 04 May 2020 02:26:14 +0800
To: root@localhost.localdomain
Subject: help
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=us-ascii
From: edward@localhost.localdomain (edward)
Status: R

I am edward . please help me.
\S
Kernel \r on an \m 

&

[root@localhost abc]# echo {1..100}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100
[root@localhost abc]# echo {1..100} | tr ' ' '+'
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+55+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70+71+72+73+74+75+76+77+78+79+80+81+82+83+84+85+86+87+88+89+90+91+92+93+94+95+96+97+98+99+100
[root@localhost abc]# echo {1..100} | tr ' ' '+' |bc 
5050
[root@localhost abc]# 

[root@localhost abc]# seq -s+ 1 100 
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+55+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70+71+72+73+74+75+76+77+78+79+80+81+82+83+84+85+86+87+88+89+90+91+92+93+94+95+96+97+98+99+100
[root@localhost abc]# seq -s + 1 100 
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+55+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70+71+72+73+74+75+76+77+78+79+80+81+82+83+84+85+86+87+88+89+90+91+92+93+94+95+96+97+98+99+100
[root@localhost abc]# seq -s + 1 100 |bc
5050
[root@localhost abc]# 

[root@localhost abc]# date
Mon May  4 03:13:31 CST 2020
[root@localhost abc]# date +%s
1588533215
[root@localhost abc]# echo `date +%s`/86400 | bc
18385
[root@localhost abc]# echo `date +%s`/86400/365 | bc
50
[root@localhost abc]#  

[root@localhost abc]# openssl rand -base64 9
oxmVEgg0TvhU
[root@localhost abc]# mkpasswd 
lcqdWF92+
[root@localhost abc]# yum install expect
[root@localhost abc]# mkpasswd -l 15 -d 3 -C 5
g82ZzI5pVq=EMud
[root@localhost abc]# 

[root@localhost abc]# pwck
user 'ftp': directory '/var/ftp' does not exist
user 'gluster': directory '/run/gluster' does not exist
user 'saslauth': directory '/run/saslauthd' does not exist
user 'pulse': directory '/var/run/pulse' does not exist
user 'gnome-initial-setup': directory '/run/gnome-initial-setup/' does not exist
pwck: no changes
[root@localhost abc]# getent passwd edward
edward:x:1000:1000:edward:/home/edward:/bin/bash
[root@localhost abc]# getent group edward
edward:x:1000:edward
[root@localhost abc]# getent group edward root
edward:x:1000:edward
root:x:0:
[root@localhost abc]# 
[root@localhost abc]# grpck
[root@localhost abc]# vipw
vipw: /etc/passwd is unchanged
[root@localhost abc]# vigr
vigr: /etc/group is unchanged
[root@localhost abc]# 

[root@localhost abc]# yum install finger -y
[root@localhost abc]# finger slackware
Login: slackware      			Name: 
Directory: /home/slackware          	Shell: /bin/bash
Never logged in.
No mail.
No Plan.
[root@localhost abc]# chfn slackware
Changing finger information for slackware.
Name []: slackware name
Office []: depops
Office Phone []: 123
Home Phone []: 456

Finger information changed.
[root@localhost abc]# finger slackware
Login: slackware      			Name: slackware name
Directory: /home/slackware          	Shell: /bin/bash
Office: depops, 123			Home Phone: 456
Never logged in.
No mail.
No Plan.
[root@localhost abc]# 

在一台机器上新建了 test1、test2、test3等用户，需要在其他机器上，也批量创建这些用户，则，需要将 /etc/passwd 里，相关用户信息复制出来，在其他机器上使用：
[root@localhost abc]# cat test.user 
test1:x:2003:2003::/home/test1:/bin/bash
test2:x:2004:2004::/home/test2:/bin/bash
test3:x:2005:2005::/home/test3:/bin/bash
[root@localhost abc]# newusers test.user
[root@localhost abc]# ls /home/
edward  linux  mandriva  slackware  test1  test2  test3

[root@localhost abc]# cat test.pass 
test1:1234
test2:5678
test3:abc123
[root@localhost abc]# cat test.pass | chpasswd
批量修改密码