Linux-practice (23-24)

23. Grep/egrep Regular Expression exercises:

1) display lines in the/etc/passwd file that do not end with bash;

For:

# grep-v "bash$"/etc/passwd

2) Locate the two-bit or three-bit integer in the result of the ifconfig command execution;

For:

# Ifconfig | grep--color=auto "\<\ ([[:d igit:]]\{2,3\}\) \>"//00

# Ifconfig | grep--color=auto "\<\ ([1-9][0-9]\|[ 1-9][0-9][0-9]\) \> "//Perfect

3) Find/etc/grub2.cfg (in the CentOS6 is/etc/grub.conf) file, a non-blank line beginning with a blank character;

For:

# Cat/etc/grub.conf | grep "^[[:space:]]\+.*[^[:space:]]$"//CENTOS6

# grep "^[[:space]]\+[^[:space:]]\+"/etc/grub2.cfg//centos7

Default=0

Sets the default boot menu item, and all the title in the entire menu is numbered starting from 0;

Timeout=5

When the user does not make a selection, Grub automatically boots the default menu corresponding to the kernel's timeout period;

Splashimage= (hd0,0)/grub/splash.xpm.gz

The path of the grub background image;

Hiddenmenu

Hide Grub's boot menu

Password--md5 Crypted_password

To protect the password set by the menu, it is often used to prevent random entry into single-user mode;

Title CentOS 6 (2.6.32-573.el6.x86_64)

Define each title in a menu item to define multiple title items;

Root (hd0,0)

Specifies the root device of grub, usually the partition that is used to install grub;

kernel/vmlinuz-2.6.32-573.el6.x86_64 ro root=uuid=5ebb0e76-bb19-4a80-9c70-0d101c0778e1 nomodeset Rd_NO_LUKS KEYBOARDTYPE=PC keytable=us rd_no_md Crashkernel=auto lang=zh_cn. UTF-8 RD_NO_LVM rd_no_dm RHGB quiet

The menu corresponds to the kernel to be launched and the parameters passed to the kernel;

Initrd/initramfs-2.6.32-573.el6.x86_64.img

RAMDisk (RAMFS) file corresponding to the kernel

Password--md5 Crypted_password

Protect the boot of the operating system kernel;

4) Find the result of "Netstat-tan" command, the line with "LISTEN" followed by any whitespace character;

For:

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

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

5) Find the result of the "fdisk-l" command, including the line with/dev/followed by SD or HD and a lowercase letter;

For:

# Fdisk-l | grep "^/dev/[s|h]d[a-z]"

6) Find all the file paths in the results of the "ldd/usr/bin/vim" command;

For:

# Ldd/usr/bin/vim | Grep-o "/[^[:space:]]\+"

# Ldd/usr/bin/vim | Grep-o "/.*/.*"

7) Find out all the lines in the/proc/meminfo file that start with uppercase s or lowercase s, how many ways do you implement the task?

For:

# Cat/proc//meminfo | grep "^[ss].*"//Memory usage

# Cat/proc//meminfo | Grep-e "^ (s|s). *"

# Cat/proc//meminfo | Grep-i "^s"//Ignore Case

# Cat/proc/meminfo | grep "^s\|^s"//note explanation output "or"

# Cat/proc/meminfo | Grep-e "^s"-E "^s"//Multiple matches

8) Use Egrep to remove the base name of a path;

For:

# Ls/usr/bin/ldd | Grep-o "/[a-z]\+$"

9) displays an integer between 0-255 in the result of the ifconfig command;

For:

# Ifconfig | grep--color=auto "\<\ ([0-9]\|[ 1-9][0-9]\|1[0-9][0-9]\|2[0-4][0-9]\|25[0-5]\) \> "

10) Add User bash, Testbash, basher, Nologin, Unlogin, logining, the default shell for the first three users is/bin/bash, the default shell for the last three users is/sbin/nologin, And then find the user name and shell name of the users of the same information;

For:

# useradd-s/bin/bash Bash

# useradd-s/bin/bash basher

# useradd-s/bin/bash Testbash

# useradd-s/sbin/nologin Nologin

# useradd-s/sbin/nologin Unlogin

# useradd-s/sbin/nologin logining//Create multi-user available scripts to complete

# CAT/ETC/PASSWD | grep "^\<\ ([[: alnum:]]\+\) \>.*\1$"

Cases:

[Email protected] ~]# grep-v "bash$"/etc/passwd

Bin:x:1:1:bin:/bin:/sbin/nologin

Daemon:x:2:2:daemon:/sbin:/sbin/nologin

......

[Email protected] ~]# Ifconfig | grep--color=auto "\<\ ([[:d igit:]]\{2,3\}\) \>"

Eth0 Link encap:ethernet HWaddr 00:0c:29:ef:91:5e

inet addr:172.16.67.2 bcast:172.16.255.255 mask:255.255.0.0

Inet6 ADDR:FE80::20C:29FF:FEEF:915E/64 Scope:link

RX bytes:638912 (623.9 KiB) TX bytes:587812 (574.0 KiB)

eth1 Link encap:ethernet HWaddr 00:0c:29:ef:91:68

inet addr:192.168.222.136 bcast:192.168.222.255 mask:255.255.255.0

Inet6 ADDR:FE80::20C:29FF:FEEF:9168/64 Scope:link

TX packets:11 errors:0 dropped:0 overruns:0 carrier:0

RX bytes:112446 (109.8 KiB) TX bytes:1334 (1.3 KiB)

Eth2 Link encap:ethernet HWaddr 00:0c:29:ef:91:72

inet addr:192.168.222.137 bcast:192.168.222.255 mask:255.255.255.0

Inet6 ADDR:FE80::20C:29FF:FEEF:9172/64 Scope:link

TX packets:175 errors:0 dropped:0 overruns:0 carrier:0

RX bytes:120635 (117.8 KiB) TX bytes:17648 (17.2 KiB)

inet addr:127.0.0.1 mask:255.0.0.0

Inet6 addr::: 1/128 scope:host

RX packets:46 errors:0 dropped:0 overruns:0 frame:0

TX packets:46 errors:0 dropped:0 overruns:0 carrier:0

[Email protected] ~]#

[Email protected] ~]# cat/etc/grub.conf

# grub.conf generated by Anaconda

#

# Note that you don't have the to rerun grub after making changes to the This file

# notice:you has a/boot partition. This means

# all kernel and INITRD paths is relative to/boot/, eg.

# root (hd0,0)

# kernel/vmlinuz-version RO root=/dev/sda2

# initrd/initrd-[generic-]version.img

#boot =/dev/sda1

Default=0

Timeout=5

Splashimage= (hd0,0)/grub/splash.xpm.gz

Hiddenmenu

Title CentOS 6 (2.6.32-573.el6.x86_64)

Root (hd0,0)

kernel/vmlinuz-2.6.32-573.el6.x86_64 ro root=uuid=1e8379ed-1b71-4c70-b97a-4d2121654719 nomodeset Rd_NO_LUKS KEYBOARDTYPE=PC keytable=us rd_no_md Crashkernel=auto lang=zh_cn. UTF-8 RD_NO_LVM rd_no_dm RHGB quiet

Initrd/initramfs-2.6.32-573.el6.x86_64.img

[Email protected] ~]#

[Email protected] ~]# cat/etc/grub.conf | grep "^[[:space:]]\+.*[^[:space:]]$"

Root (hd0,0)

kernel/vmlinuz-2.6.32-573.el6.x86_64 ro root=uuid=1e8379ed-1b71-4c70-b97a-4d2121654719 nomodeset Rd_NO_LUKS KEYBOARDTYPE=PC keytable=us rd_no_md Crashkernel=auto lang=zh_cn. UTF-8 RD_NO_LVM rd_no_dm RHGB quiet

Initrd/initramfs-2.6.32-573.el6.x86_64.img

[Email protected] ~]#

[Email protected] ~]# Netstat-tan | grep ". *listen[[:space:]]*$"

TCP 0 0 0.0.0.0:36239 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::: 111:::* LISTEN

TCP 0 0::: +:::* LISTEN

TCP 0 0::: 33813:::* LISTEN

TCP 0 0::: $:::* LISTEN

TCP 0 0:: 1:631:::* LISTEN

TCP 0 0:: 1:25:::* LISTEN

TCP 0 0:: 1:6010:::* LISTEN

[Email protected] ~]#

[Email protected] ~]# Fdisk-l | grep "^/dev/[s|h]d[a-z]"

/DEV/SDA1 * 1 204800 Linux

/dev/sda2 6553 52428800 Linux

/dev/sda3 6553 6814 2097152, Linux Swap/solaris

[Email protected] ~]#

[Email protected] ~]# Ldd/usr/bin/vim | Grep-o "/.*/.*"

/lib64/libm.so.6 (0x0000003634800000)

/lib64/libselinux.so.1 (0x0000003635400000)

/lib64/libtinfo.so.5 (0x000000363d000000)

/lib64/libacl.so.1 (0x0000003c76800000)

/usr/lib64/libgpm.so.2 (0x0000003634c00000)

/usr/lib64/perl5/core/libperl.so (0x0000003634400000)

/lib64/libdl.so.2 (0x0000003633800000)

/lib64/libpthread.so.0 (0x0000003634000000)

/lib64/libc.so.6 (0x0000003633c00000)

/lib64/ld-linux-x86-64.so.2 (0x0000003633400000)

/lib64/libattr.so.1 (0x0000003643800000)

/lib64/libresolv.so.2 (0x0000003635800000)

/lib64/libnsl.so.1 (0x0000003644c00000)

/lib64/libcrypt.so.1 (0x000000363f800000)

/lib64/libutil.so.1 (0x0000003643c00000)

/lib64/libfreebl3.so (0x000000363f400000)

[Email protected] ~]#

[Email protected] ~]# Ldd/usr/bin/vim | Grep-o "/[^[:space:]]\+"

/lib64/libm.so.6

/lib64/libselinux.so.1

/lib64/libtinfo.so.5

/lib64/libacl.so.1

/usr/lib64/libgpm.so.2

/usr/lib64/perl5/core/libperl.so

/lib64/libdl.so.2

/lib64/libpthread.so.0

/lib64/libc.so.6

/lib64/ld-linux-x86-64.so.2

/lib64/libattr.so.1

/lib64/libresolv.so.2

/lib64/libnsl.so.1

/lib64/libcrypt.so.1

/lib64/libutil.so.1

/lib64/libfreebl3.so

[Email protected] ~]#

[Email protected] ~]# Ldd/usr/bin/vim | Grep-o "/[^[:space:]]\+" | Wc-l

16

[Email protected] ~]# Ldd/usr/bin/vim | Grep-o "/.*/.*" | Wc-l

16

[Email protected] ~]# Cat/proc//meminfo | grep "^[s|s].*"

swapcached:48 KB

swaptotal:2097148 KB

swapfree:2094960 KB

shmem:3136 KB

slab:85056 KB

sreclaimable:15576 KB

sunreclaim:69480 KB

[Email protected] ~]# LS/USR/BIN/LDD | Grep-o "/[a-z]\+$"

/ldd

[Email protected] ~]#

[Email protected] ~]# Ifconfig | grep--color=auto "\<\ ([0-9]\|[ 1-9][0-9]\|1[0-9][0-9]\|2[0-4][0-9]\|25[0-5]\) \> "

[Email protected] ~]#

[Email protected] ~]# CAT/ETC/PASSWD | grep "^\<\ ([[: alnum:]]\+\) \>.*\1$"

Sync:x:5:0:sync:/sbin:/bin/sync

Shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

Halt:x:7:0:halt:/sbin:/sbin/halt

[Email protected] ~]#

24. Scripting Exercises:

1) Write a script that requires:

Statistics/etc,/Var, the sum of all non-hidden primary subdirectories and files in the/usr directory;

For:

#!/bin/bash

#

a=$ (ls/etc | wc-l)

b=$ (Ls/var | wc-l)

c=$ (ls/usr | wc-l)

count=$[$a + $b + $c]

echo "$count"

[Email protected] ~]# VI 24p1.sh

[Email protected] ~]#

[Email protected] ~]# chmod +x 24p1.sh

[Email protected] ~]#

[Email protected] ~]#./24p1.sh

303

2) Write a script that requires:

For directory/tmp/testdir1, if the current valid user has read, write, and Execute permissions, then a file is created in that directory, otherwise the message "No permissions cannot be created" is displayed.

For:

#!/bin/bash

#

Fpath=/tmp/testdir1

[-R $FPATH-W $FPATH-X $FPATH] && touch $FPATH/newdir | | echo "Don ' t right to create Useradd"

[Email protected] ~]# VI 24p2.sh

[Email protected] ~]#

[Email protected] ~]# Ll/tmp/testdir1

Total 0

[Email protected] ~]# chmod +x 24p

24p1.sh 24p2.sh

[Email protected] ~]# chmod +x 24p2.sh

[Email protected] ~]#

[Email protected] ~]#./24p2.sh

[Email protected] ~]#

[Email protected] ~]# Ll/tmp/testdir1

Total 0

-rw-r--r--. 1 root root 0 Nov 11:29 newdir

[Email protected] ~]#

3) Write a script that requires:

Select a user randomly from the same UID and GID in/etc/passwd to determine whether the user name and basic group name are the same;

For:

#!/bin/bash

#

username=$ (grep "\<\ ([[:d igit:]]\+\) .*\1\>"/etc/passwd | sort-r | head-1 | cut-d ":"-f1)

groupname=$ (id-gn $username)

[$username = = $groupname] && echo "username and group is same." | | "Username and GroupName is different."

[Email protected] ~]# VI 24p3.sh

[Email protected] ~]#

[Email protected] ~]# chmod +x 24p3.sh

[Email protected] ~]#

[Email protected] ~]#./24p3.sh

Cut:invalid option--' 1 '

Try ' Cut--help ' for more information.

./24p3.sh:line 5: [: = =: unary operator expected

./24p3.sh:line 5:username and GroupName are different.: Command not Found

[Email protected] ~]#

[Email protected] ~]# VI +5 24p3.sh

[Email protected] ~]#

[Email protected] ~]#./24p3.sh

Username and group is same.

[Email protected] ~]#

Linux-practice (23-24)