Shell finishing (26) = = = Uppercase and lowercase letters replace and randomly take out an odd number

(a) Title: Accept an input, if the uppercase letter is converted into lowercase letters, lowercase letters to uppercase.

For example:

[Email protected] hushuai]# bash 4.sh

Input:dingxue

Dingxue

[Email protected] hushuai]#

Method (1)

The shell code is as follows:

#!/bin/bash

Read-p "Input:" DD

echo $DD | TR ' [a-z][a-z] ' [a-z][a-z] '

~

Method (2)

The shell code is as follows:

#!/bin/bash

Read-p "Input word:" Word

[-Z $word] && echo "\033[32M input Word!!! \033[0m "

a=${#word}

For i in ' seq $a '

Do

B= ' echo $word | Cut-c$i '

C= ' echo $b |tr ' A-Z ' 1 '

If ["$c" = 1];then

E= ' echo $b |tr ' A-Z ' A-Z '

Else

E= ' echo $b |tr ' A-Z ' A-Z '

Fi

Echo-n $e

Done

Echo

But there are two different ways to do it, such as:

[Email protected] hushuai]# bash 3.sh

Input word:ding XUE

3.sh:line 4: [: ding:binary operator expected # error; it's because I've got one more space in between.

Dingxue

[Email protected] hushuai]# bash 3.sh

Input Word:dingxue # So it's all right.

Dingxue

[Email protected] hushuai]#

At this time we can broaden our mind, if we get rid of the problem

(1) Allow the user to enter any character, including spaces

(2) If it is not a letter, return the input value, do not make any changes

(3) If uppercase is converted to lowercase, lowercase to uppercase

For example:

[Email protected] hushuai]# bash 7.sh

Plz Input something:ding%s js

DIng%s JS

[Email protected] hushuai]#

A very good idea.

The shell code is as follows:

!/bin/bash

Swap () {

A= ' echo $ | Grep-c ' [A-z] ' # The parameters passed in can be filtered to any of [a-z]

B= ' echo $1| Grep-c ' [A-z] ' letter, definitely on one line, so the value of a and B is not 0

If [$a-eq 1];then is 1

Echo-n $ | Tr ' A-Z ' A-Z

elif [$b-eq 1];then # in the loop each time you do a change of line

Echo-n $ | Tr ' A-Z ' A-Z '-n ensures that the loop does not

else line break

Echo-n "$"

Fi

}

Read-p "Plz Input Something:" String

For i in ' seq ${#string} ' # Number of input strings, including spaces

Do

Xxoo= ' echo $string |cut-c $i '

Swap "$xxoo" # must be double quotation marks, otherwise the space is not resolved, the details of the problem

Done

Echo

Title (ii): Application of a simple random number

After executing the script from the 1-100 count, randomly pops an odd number.

The shell script code is as follows:

#!/bin/bash

For i in ' SEQ 100 '

Do

If [$ (i%2))-ne 0];then

echo $i >>123

Fi

Done

A= ' cat 123 |wc-l '

b=$ ((random% $a + 1))

Cat 123 | Sed-n ' $b ' P '

This principle is very simple, after seeing this we can also make a point roster, a list of many students in a list of names in a row, such as executing a script, random pop-up name.

My summary of the above script, personal experience:

(1) TR replacement problem:

[Email protected] hushuai]# echo ABCDSDDSFF | TR ' [a-za-z] ' [a-za-z] '

Abcdsddsff

[Email protected] hushuai]#

This can be done, but you must pay attention to the position, and do not add brackets, such as

[Email protected] hushuai]# echo ABCDSDDSFF | Tr ' a-za-z ' a-za-z '

Abcdsddsff

[Email protected] hushuai]#

But you can't write like that, and that's stupid.

[Email protected] hushuai]# echo ABCDSDDSFF | Tr ' a-za-z ' a-za-z '

Abcdsddsff

[Email protected] hushuai]#

And if you want to replace enough, what will happen, will be the last number or letter to be filled with = = For example:

[Email protected] hushuai]# echo {A.. Z} | Tr ' A-Z ' 0-9 '

0 1 2 3 4 5 6 7 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9

TR also has the often used option is tr-s compression tr-d Delete

For example: Do you see the effect? I've deleted all the blanks.

[Email protected] hushuai]# echo 123 456 | Tr-d "

123456

[Email protected] hushuai]# echo 123 456 | Tr-d ' 6 ' # Remove spaces and 6

12345

[Email protected] hushuai]# echo 123 456 | Tr-d ' 6 ' # delete only 6 do not remove spaces

123 45

[Email protected] hushuai]# echo 123 456 | Tr-d ' [6] ' # can also be written like this

12345

[Email protected] hushuai]#

For example: So, what if there are multiple lines in the text?

"[email protected] hushuai]# Cat 000

123 QWD

456 DSJ

[email protected] hushuai]# Cat 000 | cut-c-10 | Tr-d ' # to remove every line of space, so to speak

123QWD Delete is for each line in the

456dsj

[Email protected] hushuai]#

Tr-s is for a row to another line.

For example:

[[email protected] hushuai]# Cat 000

123 QWD

# There's a blank line #

O

456 DSJ

[email protected] hushuai]# Cat 000 | cut-c-10 | tr-d ' |tr-s ' \ n '

123QWD tr-d: Delete every line of space, but each row has a newline

o character, compressed in line break

456dsj

[Email protected] hushuai]#

With this we can take out the name of the network card inside the machine: for example

[Email protected] hushuai]# Ifconfig |cut-c-10 | tr-d ' |tr-s ' \ n '

Eth0

Eth1

Lo

[Email protected] hushuai]#

(3) Grep-c grep is read in a row, statistics filtered to how many rows, not how many

For example:

[Email protected] hushuai]# echo 123 | Grep-c ' [0-9] '

1

[Email protected] hushuai]# echo 123 | Grep-c ' 0-9 ' # must be enclosed in single quotes, brackets, and single quotes

0

[Email protected] hushuai]# echo 123 | grep ' [0-9] '

123

[Email protected] hushuai]# echo 123 | Grep-o ' [0-9] ' # so we can see [0-9] that

1 matches any one of the letters inside the brackets.

2 [^0-9] This means to take the inverse

3 ^[0-9] Start with any one of the 0-9 letters

This article from "It Life" blog, declined reprint!

Shell finishing (26) = = = Uppercase and lowercase letters replace and randomly take out an odd number