马哥第四周作业
1、复制/etc/skel目录为/home/tuser1，要求/home/tuser1及其内部文件的属组和其它用户均没有任何访问权限。
答：
cp -rf /etc/skel /home/tuser1
chmod -R go= /home/tuser1
2、编辑/etc/group文件，添加组hadoop。
答：echo 'hadoop:x:1500:' >> /etc/group
3、手动编辑/etc/passw d文件新增一行，添加用户hadoop，其基本组ID为hadoop组的id号；其家目录为/home/hadoop。
答：echo 'hadoop:x:1500:1500::/home/hadoop:/bin/bash' >> /etc/passwd
4、复制/etc/skel目录为/home/hadoop，要求修改hadoop目录的属组和其它用户没有任何访问权限。
答：
cp -rf /etc/skel /home/hadoop
chmod go= /home/hadoop
5、修改/home/hadoop目录及其内部所有文件的属主为hadoop，属组为hadoop。
答：chown -R hadoop:hadoop /home/hadoop
6、显示/proc/meminfo文件中以大写或小写S开头的行；用两种方式；
答：
[root@localhost ~]# cat /proc/meminfo |grep "^[s,S]" SwapCached: 0 kB SwapTotal: 2031612 kB SwapFree: 2031612 kB Shmem: 164 kB Slab: 95140 kB SReclaimable: 35124 kB SUnreclaim: 60016 kB [root@localhost ~]# grep -i '^s' /proc/meminfo SwapCached: 0 kB SwapTotal: 2031612 kB SwapFree: 2031612 kB Shmem: 164 kB Slab: 95140 kB SReclaimable: 35120 kB SUnreclaim: 60020 kB [root@localhost ~]# grep '^[sS]' /proc/meminfo SwapCached: 0 kB SwapTotal: 2031612 kB SwapFree: 2031612 kB Shmem: 164 kB Slab: 95136 kB SReclaimable: 35120 kB SUnreclaim: 60016 kB [root@localhost ~]# sed -n '/^[s,S]/p' /proc/meminfo SwapCached: 0 kB SwapTotal: 2031612 kB SwapFree: 2031612 kB Shmem: 164 kB Slab: 95136 kB SReclaimable: 35120 kB SUnreclaim: 60016 kB [root@localhost ~]#
7、显示/etc/passw d文件中其默认shell为非/sbin/nologin的用户；
答：
[root@localhost ~]# cat /etc/passwd |grep -v /sbin/nologin root:x:0:0:root:/root:/bin/bash sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt mandriva:x:1005:2016::/home/mandriva:/bin/bash mageia:x:1100:1100::/home/linux:/bin/bash slackware:x:2002:2016::/home/slackware:/bin/tcsh openstack:x:3003:2019::/home/openstack:/bin/bash [root@localhost ~]#
8、显示/etc/passw d文件中其默认shell为/bin/bash的用户；
答：
[root@localhost ~]# cat /etc/passwd |grep "\/bin\/bash$" root:x:0:0:root:/root:/bin/bash mandriva:x:1005:2016::/home/mandriva:/bin/bash mageia:x:1100:1100::/home/linux:/bin/bash openstack:x:3003:2019::/home/openstack:/bin/bash [root@localhost ~]# sed -n '/\/bin\/bash$/p' /etc/passwd root:x:0:0:root:/root:/bin/bash mandriva:x:1005:2016::/home/mandriva:/bin/bash mageia:x:1100:1100::/home/linux:/bin/bash openstack:x:3003:2019::/home/openstack:/bin/bash [root@localhost ~]#
9、找出/etc/passw d文件中的一位数或两位数；
答：
[root@localhost ~]# grep '\<[0-9]\{1,2\}\>' /etc/passwd
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
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
rpc:x:32:32:Rpcbind Daemon:/var/cache/rpcbind:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
haldaemon:x:68:68:HAL daemon:/:/sbin/nologin
ntp:x:38:38::/etc/ntp:/sbin/nologin
saslauth:x:499:76:Saslauthd user:/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
[root@localhost ~]#10、显示/boot/grub/grub.conf中以至少一个空白字符开头的行；
答:
[root@localhost ~]# grep '^[[:space:]]' /boot/grub/grub.conf root (hd0,0) kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup/lv_root KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet initrd /initramfs-2.6.32-642.el6.x86_64.img [root@localhost ~]#
11、显示/etc/rc.d/rc.sysinit文件中以#开头，后面跟至少一个空白字符，而后又有至少一个非空白字符的行；
答:
[root@localhost ~]# grep "^#[[:space:]]\+[^[:space:]]\+" /etc/rc.d/rc.sysinit # /etc/rc.d/rc.sysinit - run once at boot time # Taken in part from Miquel van Smoorenburg's bcheckrc. # Check SELinux status # Print a text banner. # Only read this once. # Initialize hardware # Set default affinity # Load other user-defined modules # Load modules (for backward compatibility with VARs) # Configure kernel parameters # Set the hostname. # Sync waiting for storage. # Device mapper & related initialization # Start any MD RAID arrays that haven't been started yet # Remount the root filesystem read-write. # Clean up SELinux labels # If relabeling, relabel mount points. # Mount all other filesystems (except for NFS and /proc, which is already # mounted). Contrary to standard usage, # filesystems are NOT unmounted in single user mode. # The 'no' applies to all listed filesystem types. See mount(8). # Check to see if a full relabel is needed # Update quotas if necessary # Initialize pseudo-random number generator # Configure machine if necessary. # Clean out /. # Do we need (w|u)tmpx files? We don't set them up, but the sysadmin might... # Clean up /var. # Clean up utmp/wtmp # Clean up various /tmp bits # Make ICE directory # Start up swapping. # Set up binfmt_misc # Boot time profiles. Yes, this should be somewhere else. # Now that we have all of our basic modules loaded and the kernel going, # let's dump the syslog ring somewhere so we can find it later # create the crash indicator flag to warn on crashes, offer fsck with timeout # Let rhgb know that we're leaving rc.sysinit [root@localhost ~]#
12、打出netstat -tan命令执行结果中以‘LISTEN’，后或跟空白字符结尾的行；
答:
[root@localhost ~]# netstat -tan | egrep "LISTTEN|[[:space:]]$" Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:36685 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp 0 0 192.168.2.55:22 192.168.2.43:55001 ESTABLISHED tcp 0 0 :::111 :::* LISTEN tcp 0 0 :::53618 :::* LISTEN tcp 0 0 :::22 :::* LISTEN tcp 0 0 ::1:631 :::* LISTEN tcp 0 0 ::1:25 :::* LISTEN [root@localhost ~]# netstat -tan | grep -P 'LISTEN\s*$' tcp 0 0 0.0.0.0:36685 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp 0 0 :::111 :::* LISTEN tcp 0 0 :::53618 :::* LISTEN tcp 0 0 :::22 :::* LISTEN tcp 0 0 ::1:631 :::* LISTEN tcp 0 0 ::1:25 :::* LISTEN
13、添加用户bash, testbash, basher, nologin (此一个用户的shell为/sbin/nologin)，而后找出当前系统上其用户名和默认shell相同的用户的信息；
答:
[root@localhost ~]# useradd bash [root@localhost ~]# useradd testbash [root@localhost ~]# useradd basher [root@localhost ~]# useradd -s /sbin/nologin nologin [root@localhost ~]# grep '^\([^:]\+\):.*/\1$' /etc/passwd sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt bash:x:3005:3005::/home/bash:/bin/bash nologin:x:3008:3008::/home/nologin:/sbin/nologin [root@localhost ~]#
