Regex to allow spaces in string - bash

Question

I can't get a string with spaces to validate. It works without spaces, but when I include a space in the string it fails. I have googled furiously but can't get it to work.

if [[ $string =~ ^"[A-Za-z ]"$ ]]; then
    # true
else 
    # false
fi

I'm not sure what I'm missing here...

Have a look at this demo. You need '^[A-Za-z ]*$' to match a string that can contain 0 or more letters or spaces. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Feb 19, 2016 at 8:58

anubhava · Accepted Answer · 2016-02-19 08:58:08Z

6

Use a variable to store your regex:

re='^[A-Za-z ]+$'

Then use it as:

[[ "string" =~ $re ]] && echo "matched" || echo "nope"
matched

[[ "string with spaces" =~ $re ]] && echo "matched" || echo "nope"
matched

If you want inline regex then use:

[[ "string with spaces" =~ ^[A-Za-z\ ]+$ ]] && echo "matched" || echo "nope"
matched

Or else use [[:blank:]] property:

[[ "string with spaces" =~ ^[A-Za-z[:blank:]]+$ ]] && echo "matched" || echo "nope"
matched

answered Feb 19, 2016 at 8:58

anubhava

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Comments

XsiSecOfficial · Accepted Answer · 2016-02-19 09:03:32Z

-3

I should instead use following regex if its always space instead..

if [[ $string =~ ^"[A-Za-z ](\s)"$ ]]; then
    # true
else 
    # false
fi

Cheers :)

answered Feb 19, 2016 at 9:03

XsiSecOfficial

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1 Comment

Tom Fenech Over a year ago

Those quotes are wrong and even if they weren't there, this pattern wouldn't permit a string with any number of characters other than 2.

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