bash - string / file name manipulation

In the following some useful bash snippets to manipulat strings / file names are listed.

Extract substrings

1. crop a consecutive substring ${string:position:length}

name=abcd123FGHI;
subStr=${name:4:3};
echo $subStr; # result is 123

2. remove beginning or end of a string

str=/path/to/my/file/123_complicated_9034.txt;

removes shortest matching suffix pattern %

withoutEnding=${str%.txt}; #
echo $withoutEnding; $ out: /path/to/my/file/123_complicated_9034

removes longest matching suffix pattern %%

withoutEnding2=${str%%_*};
echo $withoutEnding2; # out: /path/to/my/file/123

removes shortest matching prefix pattern #

withoutStart=${str#/path};
echo $withoutStart; # out: /to/my/file/123_complicated_9034.txt

removes longest matching prefix pattern ##

withoutStart2=${str##/*/};
echo $withoutStart2; # out: 123_complicated_9034.txt