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====== BASH - Get a SubString ======

===== Format =====

<code bash>
${var:start_position:length}
</code>

or

<code bash>
${var:start_position -length}
</code>

or

<code bash>
${var: -start_position -length}
</code>

or

<code bash>
${var: -start_position:length}
</code>

----

===== Return every character =====

<code bash>
var="abcdefgh"

echo ${#var:0}
</code>

returns:

<code bash>
abcdefgh
</code>

<WRAP info>
**NOTE:**  A starting position of 0 this means start at the begin; and therefore returns everything.
</WRAP>

----

===== Return a substring from a specific position =====

<code bash>
var="abcdefgh"

echo ${#var:3}
</code>

returns:

<code bash>
defgh
</code>

<WRAP info>
**NOTE:**  This 3 specifies to start from position 3.
</WRAP>

----

===== Return a substring between a string =====

<code bash>
var="abcdefgh"

echo ${#var:3:2}
</code>

returns:

<code bash>
de
</code>

<WRAP info>
**NOTE:**  This starts at position 3; and then returns the next 2 characters.
</WRAP>

----

===== Return a substring from beginning of a string =====

<code bash>
var="abcdefgh"

echo ${#var:0:2}
</code>

returns:

<code bash>
ab
</code>

<WRAP info>
**NOTE:**  This starts at position 0; and then returns the next 2 characters.
</WRAP>


----

===== Return last few characters from back of a string =====

<code bash>
var="abcdefgh"

echo ${#var: -4}
</code>

returns:

<code bash>
efgh
</code>

<WRAP info>
**NOTE:**  This returns the last 4 characters.

There must be a SPACE before the minus sign!

Be aware that if the length after the colon is longer than the string, then nothing is returned.
</WRAP>

----

===== Return a substring from back of a string =====

<code bash>
var="abcdefgh"

echo ${#var -1 -3}
</code>

returns:

<code bash>
efgh
</code>

<WRAP info>
**NOTE:**  This returns the last character; and 3 extra characters.

There must be a SPACE before the minus signs.

Be aware that if the length of any position is longer than the string, then nothing is returned.
</WRAP>

----

===== Substrings with Concatenation =====


<code bash>
var="abcdefgh"
echo ${var:0:(-1 -4)}XYZ
</code>

returns:

<code bash>
abcXYZ
</code>

----

===== Extracting Substrings Using Cut =====

**cut** can be used to ‘cut’ a portion of a string, aka the substring.

<code bash>
#!/bin/bash
Str="My name is Peter"
#subStr=${Str:0:6}

subStr=$(echo $Str| cut -d ' ' -f 1-3)
echo $subStr
</code>

----