Work week four: Linux basics

Content of this week's job:

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.

# Ls/home/tuser1 | | Mkdir/home/tuser1 && cp-r/etc/skel/*/home/tuser1 && chmod-r g-r,o-r/home/tuser1 | Ls-l/home/tuser1

-RW-------. 1 root root 0 August 10:59 a.txt

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

# Vim/etc/group

Add a line to the end of the file: hadoop:x:139:

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

Hadoop:x:139:139::/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.

# Ls/home/hadoop | | Mkdir/home/hadoop && cp-r/etc/skel/*/home/hadoop && chmod g-r,o-r/home/hadoop | Ls-ld/home/hadoop

DRWX------. 4 Hadoop hadoop 4096 August 10:50/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:hadoop/home/hadoop | Ls-ld!$ && Ls-la!$

Chown-r Hadoop:hadoop/home/hadoop | Ls-ld/home/hadoop && Ls-la/home/hadoop
DRWX------. 4 Hadoop hadoop 4096 August 10:50/home/hadoop
Total dosage 20
-RW-------. 1 Hadoop hadoop 0 August 10:57 a.txt
-RW-------. 1 Hadoop hadoop 18 May 05:21. bash_logout
-RW-------. 1 Hadoop hadoop 176 May 05:21. Bash_profile
-RW-------. 1 Hadoop Hadoop 124 May 05:21. BASHRC
Drwx--x--x. 2 Hadoop hadoop 4096 November gnome2
Drwx--x--x. 4 Hadoop hadoop 4096 July 22:17. Mozilla

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

# grep ^[SS]/proc/meminfo

swapcached:0 KB
swaptotal:2031612 KB
swapfree:2031612 KB
shmem:4028 KB
slab:85816 KB
sreclaimable:19592 KB
sunreclaim:66224 KB

# grep-i ^s/proc/meminfo

swapcached:0 KB
swaptotal:2031612 KB
swapfree:2031612 KB
shmem:4028 KB
slab:85812 KB
sreclaimable:19588 KB
sunreclaim:66224 KB

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

# grep-v "/sbin/nologin"/etc/passwd | Cut-d:-f1,7

Root:/bin/bash
Sync:/bin/sync
Shutdown:/sbin/shutdown
Halt:/sbin/halt
Admin:/bin/bash
Mageia:/bin/bash
Slackware:/bin/bash
Openstack:/bin/bash
Hadoop:/bin/bash
Gdm:/bin/bash
Abc:/bin/bash
Asd:/bin/bash
Asdd:/bin/bash
Lll:/bin/bash
Gentoo:/bin/csh

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

# grep "/bin/bash"/etc/passwd | Cut-d:-f1

Root
Admin
Mageia
Slackware
OpenStack
Hadoop
Gdm
Abc
Asd
Asdd
lll

9. Find out one or two digits in/ETC/PASSW D file;

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

# grep-e "\<[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

Root (hd0,0)
kernel/vmlinuz-2.6.32-642.el6.x86_64 ro root=/dev/mapper/vg_mycentosl68-lv_root Rd_NO_LUKS rd_LVM_LV=vg_ Mycentosl68/lv_swap crashkernel=auto rd_no_md rd_lvm_lv=vg_mycentosl68/lv_root LANG=zh_CN. UTF-8 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

# grep-e "^#[[: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-NFS and/proc, which is already
# mounted). Contrary to standard usage,
# filesystems is 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 is somewhere else.
# Now then 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's rhgb know that we ' re leaving 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;

# Netstat-tan | grep "listen[[:space:]]*$"

TCP 0 0 0.0.0.0:44877 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 0 127.0.0.1:6010 0.0.0.0:* LISTEN
TCP 0 0::: 37831:::* LISTEN
TCP 0 0::: 111:::* LISTEN
TCP 0 0::: $:::* LISTEN
TCP 0 0:: 1:631:::* LISTEN
TCP 0 0:: 1:25:::* LISTEN
TCP 0 0:: 1:6010:::* LISTEN

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 basher && useradd-s/sbin/nologin nologin

# 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:3011:3013::/home/bash:/bin/bash
Nologin:x:3014:3016::/home/nologin:/sbin/nologin

Note: For personal work and learning purposes only

Work week four: Linux basics