Shell script - function to split a string based on a delimiter

#!/bin/ksh

#function to split a string based on a delimiter
function split {

        string=$1
        delimiter=$2

echo "split string '"$string"' with delimiter '"$delimiter"'"
        for word in $(echo $string | tr "$delimiter" "\n")
        do
                echo $word
        done
}

#call the split function with arguments string and delimiter
split "transient;private;protected;public;synchronized;native" ";"

split "float|short|char|double" "|"

UNIX/LINUX - How to encrypt/decrypt a text file

crypt command can be used to encrypt/decrypt a particular text file in UNIX/LINUX. It is a simple encryption algorithm which works on a secret-key basis. It encrypts or decrypts a stream of data from standard input, and writes the result to standard output. Encryption and decryption is a symmetric process.

Encryption
This will create an encrypted file enTextFile.txt  from a text file textFile.txt. You can use either of the commands both does one and the same task.

crypt ENCRYPTION_KEY < textFile.txt > enTextFile.txt

OR

cat textFile.txt | crypt > enTextFile.txt

Decryption
This will decrypt an encrypted file enTextFile.txt and store the output in textFile.txt

crypt ENCRYPTION_KEY < enTextFile.txt (to show data on console)
crypt ENCRYPTION_KEY < enTextFile.txt > textFile.txt

OR

cat enTextFile.txt | crypt > textFile.txt

Linux - Copy/paste block of codes from Windows editor to Vi editor

Below is the command used to Copy/paste a block of code(s) from Windows editor to Vi editor. Basically to replace complete text from a particular file.

First copy the block of code(s) from windows editor then go to Vi editor and use the following command sequentially as given below

<ESC>
d
Shift+g
i
Shift+Insert
<ESC>

Above command says delete (d) the codes form specific line number (0 in this case) upto end of the file i.e. last line (note - capital G, hence Shift+g). Then go to insert mode (i) and paste the copied lines.

Linux - Block of comments in shell script

There is no block comment on shell script however there are few options that you can try out -

Method 1

#!/bin/bash
echo "This is a statement"
: << 'COMMENTS'
echo "The code that you want be commented out goes here"
echo "This echo statement will not be called"
COMMENTS
echo "This statement is outside the comment block"

At the beginning of the block you wish to comment out put -
: << 'COMMENTS'

The '' around the COMMENTS delimiter is important, otherwise things inside the block will be parsed and executed. I have used 'COMMENTS' as it should be a string of characters which is not used in you code, modify it in your code if needed.

And at the end of the block put -
COMMENTS

Method 2

#!/bin/bash
echo "This is a statement"
if [ 1 -eq 0 ]; then
echo "The code that you want be commented out goes here"
echo "This echo statement will not be called"
fi
echo "This statement is outside the comment block"

Added a false condition in the IF block so that it won't get executed.

Method 3

Using vi editor you can easily comment/uncomment from line n to m

Comment

<ESC>
:10,100s/^/#/

Above command says from line 10 to 100 substitute line start (^) with a # sign

Uncomment

<ESC>
:10,100s/^#//

Above command says from line 10 to 100 substitute line start (^) followed by # with noting //