Bash += and -=: Difference between revisions

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=Internal=
=Internal=
* [[Bash_Concepts#.2B.3D|bash Concepts]]
* [[Bash_Concepts#.2B.3D|bash Concepts]]
* [[((...))|((...))]]


=Overview=
=Overview=
Line 17: Line 18:
1
1
</syntaxhighlight>
</syntaxhighlight>
The += can be used on string values as such:
Also:
<syntaxhighlight lang='bash'>
<syntaxhighlight lang='bash'>
i=0
((i-=1))
echo ${i}
</syntaxhighlight>
displays:
<syntaxhighlight lang='bash'>
-1
</syntaxhighlight>
</syntaxhighlight>
+= can be used on string values as such:
<syntaxhighlight lang='bash'>
s="something"
s+=" else"
echo ${s}
</syntaxhighlight>
displays:
<syntaxhighlight lang='text'>
something else
</syntaxhighlight>
-= does not work with strings.

Latest revision as of 05:39, 8 May 2020

External

Internal

Overview

+= and -= are assignment operators that can be used to increment/decrement the value of the left operand with the value specified after the operator. The operators can be used on integral values as such:

i=0
((i+=1))
echo ${i}

displays:

1

Also:

i=0
((i-=1))
echo ${i}

displays:

-1

+= can be used on string values as such:

s="something"
s+=" else"
echo ${s}

displays:

something else

-= does not work with strings.