Linux基础第四周作业
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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 -r /etc/skel /home/tuser1
#chmod -R 700 /home/tuer1
2、编辑/etc/group文件,添加组hadoop。
答:1.#vim /etc/group
#在最后一行添加hadoop:x:1008:
2.echo “hadoop:x:1008:”>> /etc/group
3.groupadd hadoop
[[email protected] ~]# tail -3 /etc/group
basher:x:1006:
nologin:x:1007:
hadoop:x:1008:
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:1.#vim /etc/passwd
#hadoop:x:1008:1008::/home/hadoop:/bin/bash
2.useradd hadoop -g hadoop
3.echo “hadoop:x:1008:1008::/home/hadoop:/bin/bash”>> /etc/passwd
[[email protected] ~]# tail -1 /etc/passwd
hadoop:x:1008:1008::/home/hadoop:/bin/bash
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 -r /etc/skel /home/hadoop
#chmod -R 700 /home/hadoop
[[email protected] /]# cp -r /etc/skel /home/hadoop
[[email protected] /]# chmod -R 700 /home/hadoop
[[email protected] /]# ll /home/hadoop/
总用量 0
drwx------. 3 root root 74 8月 28 20:54 skel
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
[[email protected] /]# chown -R hadoop.hadoop /home/hadoop/
[[email protected] /]# ll /home/hadoop
总用量 0
drwx------. 3 hadoop hadoop 74 8月 28 20:54 skel
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:1.grep ‘^[sS]’ /proc/meminfo
2.grep -i ‘^s’/proc/meminfo
3.sed -n ‘/^[sS]/p’ /proc/meminfo
4.awk ‘/^[sS]/’ /proc/meminfo
[[email protected] /]# grep ^[sS]p’roc/meminfo
SwapCached: 85460 kB
SwapTotal: 2097148 kB
SwapFree: 1813440 kB
Shmem: 10288 kB
Slab: 100628 kB
SReclaimable: 51180 kB
SUnreclaim: 49448 kB
7、显示/etc/passwd文件中其默认shell为非/sbin/nologin的用户;
答:1.grep -v ‘/sbin/nologin$’/etc/passwd | cut -d: -f1
2.awk -F: ‘!/\/sbin/nologin/{print $1}’/etc/passwd
[[email protected] /]# grep -v ‘/sbin/nologin‘ /etc/passwd|cut -d: -f1,7
root:/bin/bash
sync:/bin/sync
shutdown:/sbin/shutdown
halt:/sbin/halt
amandabackup:/bin/bash
mysql:/bin/bash
mysq:/bin/bash
user1:/bin/bash
user2:/bin/bash
bash:/bin/bash
testbash:/bin/bash
basher:/bin/bash
hadoop:/bin/bash
8、显示/etc/passw d文件中其默认shell为/bin/bash的用户;
答:1.grep ‘/bin/bash$’/etc/passwd | cut -d: -f1,7
2.awk -F: ‘/\/bin/bash$/{print $1,$7}’/etc/passwd
[[email protected] /]# awk -F: ‘/\/bin\/bash$/{print $1 , $7}‘ /etc/passwd
root /bin/bash
amandabackup /bin/bash
mysql /bin/bash
mysq /bin/bash
user1 /bin/bash
user2 /bin/bash
bash /bin/bash
testbash /bin/bash
basher /bin/bash
hadoop /bin/bash
9、找出/etc/passwd文件中的一位数或两位数;
答:1.grep ‘\<[0-9]\{1,2\}\>’ /etc/passwd
2.grep -E ‘\<[0-9]{1,2}\>’ /etc/passwd
3.egrep ‘\<[[:digit:]]{1,2}\>’/etc/passwd
[[email protected] /]# 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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
amandabackup:x:33:6:Amanda user:/var/lib/amanda:/bin/bash
saslauth:x:994:76:Saslauthd user:/run/saslauthd:/sbin/nologin
rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin
ntp:x:38:38::/etc/ntp:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
radvd:x:75:75:radvd user:/:/sbin/nologin
gdm:x:42:42::/var/lib/gdm:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
10、显示/boot/grub/grub.conf中以至少一个空白字符开头的行;
答:1.cat /boot/grub/grub.conf|grep ‘^[[:space:]]’
2.grep ‘^[[:space:]]’ /boot/grub/grub.conf
[[email protected] ~]# grep ‘^[[:space:]]‘ /boot/grub/grub.conf
root (hd0,0)
kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=UUID=95f5aeee-4932-4521-8a87-7134ed8ae784 rd_NO_LUKS rd_NO_LVM.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
initrd /initramfs-2.6.32-642.el6.x86_64.img
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:
1.grep ‘^#[[:space:]]\+[^[:space:]]\+’/etc/rc.d/rc.sysinit
2.egrep ‘^#[[:space:]]+[^[:space:]]’ /etc/rc.d/rc.sysinit
[[email protected] ~]# egrep ‘^#[[: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
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:netstat -tan | grep ‘LISTEN[[:space:]]*$’
[[email protected] ~]# netstat -tan|grep --color=auto ‘LISTEN[[:space:]]*$‘
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 :::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:#useradd bash
#useradd testbash
#useradd basher
#useradd nologin -s /sbin/nologin
#grep ‘^\([[:alnum:]]\+\>\).*\1$’ /etc/passwd
#egrep ‘^([[:alnum:]]+\>).*\1$’ /etc/passwd
[[email protected] ~]# tail -5 /etc/passwd
user2:x:1003:1003::/home/user2:/bin/bash
bash:x:1004:1004::/home/bash:/bin/bash
testbash:x:1005:1005::/home/testbash:/bin/bash
basher:x:1006:1006::/home/basher:/bin/bash
nologin:x:1007:1007::/home/nologin:/sbin/nologin
[[email protected] /]# grep ‘\(^[[:alnum:]]\+\>\).*\1$‘ /etc/passwd
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
bash:x:1004:1004::/home/bash:/bin/bash
nologin:x:1007:1007::/home/nologin:/sbin/nologin
[[email protected] /]# egrep ‘^([[:alnum:]]+\>).*\1$‘ /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:1004:1004::/home/bash:/bin/bash
nologin:x:1007:1007::/home/nologin:/sbin/nologin
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