Linux Random entry

1, the Replication/etc/skel directory is/home/tuser1, requires/home/tuser1 and its internal files belong to the group and other users do not have any access rights.

[Email protected]/]# cp-r/etc/skel/home/tuser1 && chmod 700-r/home/tuser1 [[email protected]/]# echo $?0[ [Email protected] home]# ll-al/home/tuser1/total dosage 12drwx------. 3 root root 74 November 13:14. Drwxr-xr-x. 4 root root 30 November 30 13:14.. -RWX------. 1 root root 18 November 13:14. bash_logout-rwx------. 1 root root 193 November 13:14. bash_profile-rwx------. 1 root root 231 November 13:14. bashrcdrwx------. 4 root root 37 November 13:14 Mozilla

2. Edit the/etc/group file and add the group Hadoop.

[[email protected]/] #echo "hadoop:x:1001" >>/etc/group [[email protected]/]# Cat/etc/group |grep Hadoop had oop:x:1001 [[Email protected]/]#

3. Manually edit the/etc/passwd file to add a new line, adding user Hadoop, whose basic group ID is the Hadoop group ID number; its home directory is/home/hadoop.

[Email protected] home]# echo "Hadoop:x:1001:1001:hadoop:/home/hadoop:/bin/bash" >>/etc/passwd && Tail -N 2/etc/passwd User:x:1000:1000:user:/home/user:/bin/bash Hadoop:x:1001:1001:hadoop:/home/hadoop:/bin/bash

4. Copy the/etc/skel directory as/home/hadoop, which requires that the genus Group and other users of the Hadoop directory be modified without any access rights.

    [[email protected] /]# cp -r /etc/skel /home/hadoop  && chmod 700 -r /home/hadoop && ll -al /home/ hadoop/     Total dosage  12    drwx------.  3 root root   74 11 Month  30 13:54 .    drwxr-xr-x. 5 root root   43 11 month  30 13:54      -rwx------.  1 root root  18 11 Month  30 13:54  . bash_logout    -rwx------.  1 root root 193 11 Month  30  13:54 .BASH_PROFILE    -RWX------.  1 root root 231 11 Month   30 13:54 .BASHRC    DRWX------.  4 root root  37  November  30 13:54 .mozilla    [[email protected] /]# 

5, modify the/home/hadoop directory and all the internal files of the owner of Hadoop, belong to Hadoop group.

    [[email protected] /]# chown -r hadoop:hadoop /home/ Total dosage of hadoop/ && ll -al /home/hadoop/      12     drwx------.  3 hadoop hadoop  74 11 Month  30 13:54 .     drwxr-xr-x. 5 root   root    43 11 month   30 13:54&NBSP, ....     -rwx------.  1 hadoop hadoop  18 11 Month  30 13:54  .bash_logout    -rwx------.  1 hadoop hadoop 193 11 Month  30  13:54 .BASH_PROFILE    -RWX------.  1 hadoop hadoop 231  11 month  30 13:54 .bashrc    drwx------.  4 hadoop hadoop   37 11 Month  30 13:54 .mozilla    [[email protected] / ]#

6. Display the lines in the/proc/meminfo file beginning with uppercase or lowercase s, in two ways;

    [[email protected] /]# grep -i  "^s"  /proc/meminfo     swapcached:            0 kb     SwapTotal:       1023996 kB     swapfree:        1023996 kb    shmem:               9636 kB     slab:             171236 kb     SReclaimable:      99660 kB     sunreclaim:        71576 kb    [[email  protected] /]# grep -i  "^[ss"  /proc/meminfo    SwapCached:             0 kB    SwapTotal:        1023996 kB    SwapFree:         1023996 kB    Shmem:               9636 kB    Slab:              171236 kB    SReclaimable:       99660 kB    SUnreclaim:         71576 kb    [[email protected] /]#

7. Display the default shell of the/etc/passwd file as a non-/sbin/nologin user;

    [[email protected] /]# grep -v  "/sbin/nologin"  /etc/ passwd    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    amandabackup:x:33:6:amanda user:/var/lib/amanda:/bin/bash     USER:X:1000:1000:USER:/HOME/USER:/BIN/BASH    HADOOP:X:1001:1001: hadoop:/home/hadoop:/bin/bash    [[email protected] /]#      cut, beautiful     [[email protected] /]# grep -v  "/sbin/nologin"  /etc/passwd | cut -d ":"  -f1    root    sync     shutdown    halt    amandabackup     user    hadoop    [[email protected] /]# 

8. Display the user whose default shell is/bin/bash in/etc/passwd file;

[[email protected]/]# grep "/bin/bash"/etc/passwd root:x:0:0:root:/root:/bin/bash Amandabackup:x:33:6:amanda User :/var/lib/amanda:/bin/bash User:x:1000:1000:user:/home/user:/bin/bash hadoop:x:1001:1001:hadoop:/home/hadoop:/ Bin/bash cut, beautiful [[email protected]/]# grep "/bin/bash"/etc/passwd |cut-d ":"-f1 root amandabackup Use R Hadoop [[email protected]/]#

9. Find out one or two digits in the/etc/passwd file;

grep "\<[0-9]\{1,2\}\>"/etc/passwd

650) this.width=650; "src=" Http://i.imgur.com/PZkXS4z.png "style=" margin-top:0px;margin-right:0px;margin-bottom:0 px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;border-top-width:0px; border-right-width:0px;border-bottom-width:0px;border-left-width:0px; "alt=" Pzkxs4z.png "/>

10. Display the line beginning with at least one blank character in/boot/grub/grub.conf;

    [[email protected] ~]# grep  "^[[:space:]]\+"  /boot/grub/ grub.conf        root  (hd0,0)          kernel /vmlinuz-2.6.32-642.3.1.el6.x86_64 ro root=/dev/mapper/vg_centos-lv_root  rd_no_luks rd_lvm_lv=vg_centos/lv_swap rd_no_md lang=zh_cn. Utf-8 rd_lvm_lv=vg_centos/lv_root  keyboardtype=pc keytable=us rd_no_dm rhgb  quiet crashkernel=auto        initrd / initramfs-2.6.32-642.3.1.el6.x86_64.img        root  (hd0,0)          kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=/dev/ Mapper/vg_centos-lv_root rd_no_luks rd_lvm_lv=vg_centos/lv_swap rd_no_md lang=zh_cn. Utf-8 rd_lvm_lv=vg_centos/lv_root  keyboardtype=pc keytable=us rd_no_dm rhgb quiet        initrd / Initramfs-2.6.32-642.el6.x86_64.img

11, the display/etc/rc.d/rc.sysinit file with the beginning of #, followed by at least one white space character, and then have at least one non-whitespace character line;

grep "^#[[:space:]]\+[^[:space:]]\+"/etc/rc.d/rc.sysinit

12. Find the line ending with ' LISTEN ' followed by 0, 1, or more whitespace characters in the result of the "Netstat-tan" command;

    [[email protected] /]# netstat -tan | grep   " 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      0 127.0.0.1:6010           0.0.0.0:*                LISTEN         tcp6        0      0 :::22                    :::*                      LISTEN          tcp6       0       0 ::1:631                 :::*                       Listen         tcp6       0       0 ::1:25                   :::*                      LISTEN          tcp6       0      0 : : 1:6010                :::*                      LISTEN         [[email protected] /]# 

13, add user bash, Testbash, basher, Nologin (this one user's shell is/sbin/nologin), and then find the current system on its user name and the default shell of the same user information;

useradd-d/home/bash-s/bin/bash-m bash useradd-d/home/testbash-s/bin/bash-m testbash useradd-d/home/bashe R-s/bin/bash-m basher useradd-d/home/nologin-s/sbin/nologin-m nologin [[email protected]/]# CAT/ETC/PASSW D | grep "^\<bash\>" bash:x:1002:1002::/home/bash:/bin/bash [[email protected]/]#

Linux scrambling