grep not giving expected result

Question

I am having trouble understanding following grep operation

a=jQuery.Uno echo $a | grep -i "jquerya*"

why is above query returning jQuery.Uno?

Mark Setchell · Accepted Answer · 2014-05-23 07:42:55Z

The * quantifier matches 0 (zero) or more.

In the string, jQuery.Uno there is 0 a after y. As such, the regex jquerya* matches the string.

If you wanted one or more of a, then instead say:

grep -i "jquerya\{1,\}"

or, if your version of grep supports extended regular expressions:

grep -iE "jquerya+"

Moreover, instead of echo "$var" | grep ..., it is better to make use of herestrings if your shell supports those:

grep -iE "jquerya+" <<< "$a"

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