Initial knowledge of vim and regular expressions

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.

~]# mkdir /home/tuser1~]# cp -r /etc/skel /home/tuesr1~]# chmod -R go-rwx /home/tuser1

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

~]# vim /etc/group    # i键进入编辑模式~]# hadoop:x:1000:    # esc 退出编辑状态~]# :wq 保存提出

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.

~]# vim /etc/passwd    # i键进入编辑模式~]# hadoop:x:1001:1000::/home/hadoop:/bin/bash    # esc 退出编辑状态~]# :wq 保存提出

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.

~]# cp -r /etc/skel /home/hadoop~]# chmod -R go-rwx /home/hadoop

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

~]# chown -R hadoop /home/hadoop~]# chgrp -R hadoop /home/hadoop

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

~]# grep -i "^s" /proc/meminfo~]# grep "^[sS]" /proc/meminfo~]# grep -E "^(s|S)" proc/meminfo

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

~]# grep -v "/sbin/nologin$" /etc/passwd | cut -d ‘:‘ -f1

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

~]# grep "/bin/bash$" /etc/passwd | cut -d ‘:‘ -f1

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

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

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

~]# grep "^[[:space:]]" /boot/grub/grub.conf

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:]]\+[[:alnum:]]" /etc/rc.d/rc.sysinit

12, the Netstat-tan command execution results in the "LISTEN", followed by or with a blank character end of the line;

~]# netstat -tan | grep "^LISTEN[[:space:]]*$"

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 bash~]# useradd testbash ~]# useradd bahser~]# useradd -s /sbin/nologin nologin~]# grep  -E  "^([^:]+\>).*\1$"  /etc/passwd

Initial knowledge of vim and regular expressions