How do you append to an already existing string?

Question

I want append to a string so that every time I loop over it, it will add "test" to the string.

Like in PHP you would do:

$teststr = "test1\n"
$teststr .= "test2\n"
echo = "$teststr"

Returns:

test1
test2

But I need to do this in a shell script

Berwickupontweed

Answer 1

In classic sh, you have to do something like:

s=test1
s="${s}test2"

(there are lots of variations on that theme, like s="$s""test2")

In bash, you can use +=:

s=test1
s+=test2

Congeries

Answer 2

$ string="test"
$ string="${string}test2"
$ echo $string
testtest2

Seafowl

Answer 3

teststr=$'test1\n'
teststr+=$'test2\n'
echo "$teststr"

Morality

Answer 4

#!/bin/bash
message="some text"
message="$message add some more"

echo $message

some text add some more

Anastrophe

Answer 5

VAR=$VAR"$VARTOADD(STRING)"   
echo $VAR

Mcatee

Answer 6

thank-you Ignacio Vazquez-Abrams

i adapted slightly for better ease of use :)

placed at top of script

NEW_LINE=$'\n'

then to use easily with other variables

variable1="test1"
variable2="test2"

DESCRIPTION="$variable1$NEW_LINE$variable2$NEW_LINE"

OR to append thank-you William Pursell

DESCRIPTION="$variable1$NEW_LINE"
DESCRIPTION+="$variable2$NEW_LINE"

echo "$DESCRIPTION"

Earthly

Why not just do DESCRIPTION="${variable1}\n${variable2}\n" ? Seems like a cleaner way to achieve the same thing, unless I'm missing something. – Berwickupontweed

there is a difference, ive just tested it. with that method i need -e if im to echo it, with what i suggested you don't. so theirs deffo a difference! – Earthly

Answer 7

#!/bin/bash

msg1=${1} #First Parameter
msg2=${2} #Second Parameter

concatString=$msg1"$msg2" #Concatenated String
concatString2="$msg1$msg2"

echo $concatString 
echo $concatString2

Arleyne