CODEWITHSUNDEEP
linuxbashshelldebian
TrueBlue10
TrueBlue10

Reputation: 418

Exchange the position of two string through bash

I want to exchange the position of two string like 1A to A1, 2B to B2

Is that possible in bash?

Now I'm doing it in a stupid way

case "$Zone" in
                    1A)
                        Zone="A1"
                        ;;
                    2A)
                        Zone="A2"
                        ;;
                    3A)
                        Zone="A3"
                        ;;
                    4A)
                        Zone="A4"
                        ;;
                    1B)
                        Zone="B1"
                        ;;
                    2B)
                        Zone="B2"
                        ;;
                    3B)
                        Zone="B3"
                        ;;
                    4B)
                        Zone="B4" 
                        ;;
                    E)
                        Zone="E" 
                        ;;
                esac

Is there any way smarter?

Upvotes: 1

Views: 97

Answers (4)

dave sines
dave sines

Reputation: 1

Use the substring expansion to obtain the second and first characters of the string:

Zone=${Zone:1:1}${Zone:0:1}

Upvotes: 0

Harsh Daftary
Harsh Daftary

Reputation: 2653

If reverse a string works then give it a try

x=$(echo $zone | rev)

Hope it helps:)

Upvotes: 2

Kent
Kent

Reputation: 195059

your requirement is not clear, what are the possibilities of input? if only number + A or B pattern is valid, and needs to be processed?

I assume you need that validation, and this one-liner does that job:

awk -v FS=''  '/^[1-5][A-L]$/{$0=$2""$1}7'

some examples:

kent$  echo "1A
2A
3B
3X
E
foo"|awk -v FS=''  '/^[1-5][A-L]$/{$0=$2""$1}7'
A1
A2
B3
3X
E
foo

you see that only if

  • the string has length 2
  • and starting with one number in range [1-5]
  • and ending with A-L

it would be get reversed, otherwise, it keeps untouched.

Upvotes: 3

fedorqui
fedorqui

Reputation: 289725

If you happen to only have strings with 1 or 2 characters, you can reverse them. And oh, there is the rev command in UNIX:

zone=$(echo "$zone" | rev)

or even shorter

zone=$(rev <<< "$zone")

See examples:

$ zone="E"
$ rev <<< "$zone"
E

$ zone="A1"
$ rev <<< "$zone"
1A

From man rev:

 rev — reverse lines of a file or files

Upvotes: 3

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