2014 Horse linux0218-1 character test and generate script code for interactive options table

0218 lesson, first a simple small program, pay attention to the use of character testing, it is recommended that all the characters tested to be quoted, and in the character test matching mode (can also make regular expressions), the need to use double brackets, the topic is as follows:

Exercise: Determine if all users have a login shell

#!/bin/bash

For UserName in ' cut-d:-f1/etc/passwd ';d o

if [[' grep ' ^ $userName \> "/etc/passwd | cut-d:-f7 ' =~ sh$]]; Then

echo "Login User: $userName"

Else

echo "Nologin User: $userName"

Fi

Done

In the question, the more bizarre is that the first half of the decision can be referenced with the grep command, do not need to add double quotes, magic!

Exercise: Write a script

1, let the user interactively enter a user name, first determine whether the user exists, does not exist, then 7 for the exit code;

2, judge whether the user's shell is/bin/bash, if it is, it is displayed as "Bash User", the exit code is 0;

Otherwise, it is displayed as "not Bash User." And the exit code is 1.

Read-p "Please input usename:" username

if! grep "^ $username/>"/etc/passwd &>/dev/null;then

Exit 7

Elif

[[' grep ^ $username/>/etc/passwd |cut-d:-f7 ' =~/bin/shell]];then

echo "Bash user"

Exit 0

Else

echo "Not bash user"

Exit 1

The above question, taken from the Xueyou notes

Exercise: 1, display the following menu:

CPU) Show CPU Info

MEM) Show Memory info

Quit) quit

Enter your option:

2, if the user chooses the CPU, displays the file/proc/cpuinfo information

3, if the user selects men, then displays the information of the file/proc/meminfo

4, if the user chooses quit, then exits, and the exit code is 5;

5. If the user types other characters, the unknown option is displayed, please re-execute the script, exit code is 6.

The following answer is a simple version of the default user input lowercase option:

#!/bin/bash

Cat <<eof

Cpu:show CPU Info

Mem:show Memory Info

Quit:quit

Eof

Read-p "Enter your option:" Useroption

If ["$userOption" = = "CPU"] &>/dev/null;then

Cat/proc/cpuinfo

elif ["$userOption" = = "Mem"] &>/dev/null;then

Cat/proc/meminfo

elif ["$userOption" = = "Quit"] &>/dev/null;then

Exit 5

Else

echo "Bad input, try again." && Bash cpuinfo.sh

Fi

The following answer is the version that accepts the user-case command:

#!/bin/bash

Cat <<eof

Cpu:show CPU Info

Mem:show Memory Info

Quit:quit

Eof

Read-p "Enter your option:" Useroption

if [["$userOption" =~ [Cc][pp][uu]] &>/dev/null;then

Cat/proc/cpuinfo && Bash cpuinfo2.sh

elif [["$userOption" =~ [mm][ee][mm]] &>/dev/null;then

Cat/proc/meminfo && Bash cpuinfo2.sh

elif [["$userOption" = = [Qq][uu][ii][tt]]] &>/dev/null;then

Exit 5

Else

echo "Bad input, try again." && Bash cpuinfo2.sh

Fi

The last question is written by oneself, two versions, own run without error, hope that friends can debug.

After completing these, I met the legendary vim! The first is to learn how to quit vim, haha haha!

2014 Horse linux0218-1 character test and generate script code for interactive options table