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AgileSoul
Asked: 2022-04-29 19:15:58 +0800 CST 2022-04-29 19:15:58 +0800 CST

How do I compare a regular expression saved in a variable?

  • 772

I have an array of strings where the elements have different colors and I want to filter the strings that have the brown color.

#!/bin/bash
cafeRegex='^\e[0;33m*{*}\e[0m$'
arrayColores=($(echo -e "\e[0;33m3tia01\e[0m \e[0;37mabuela32\e[0m 2Yo3 \e[1;37mabuelo21\e[0m 
\e[0;32m49hijo1\e[0m \e[0;36m8papa\e[0m \e[0;33m33mama11\e[0m"))
echo "El array: ${arrayColores[*]}"
for familiar in ${arrayColores[*]}
do
    if [[ $familiar =~ $cafeRegex ]]; then
        echo "Los familiares cafes son: $familiar"
    fi
done

The output I have is this:

enter image description here

It shows me the array with its colors but the sentence to filter the brown color is not executed, I suspect the regular expression.

regex

1 Answers

  1. Best Answer

    The problem is in the regular expression you define: ^\e[0;33m*{*}\e[0m$. This does not match, in regular expression terms, any of the strings you provide.

    I understand that what you want to look for is something like:

    • \e[0;33m3tia01\e[0m
    • \e[0;33m33mama11\e[0m

    But note that this includes characters like "" or "[" which cannot be set as-is, but must be escaped. Also, you mention some *I understand that to refer to any character, but its use is incorrect: it *indicates quantity, while it is .what we use to match any character.

    Therefore, the expression should be like this:

    ^\\e\[0\;33m.*\\e\[0m$

    This will match the strings that...

    • start with "\e[0;33m"
    • followed by many (or no) characters
    • and end with "\e[0m"

    Therefore, your complete script would be:

    #!/bin/bash

cafeRegex='^\\e\[0\;33m.*\\e\[0m$'
arrayColores=("\e[0;33m3tia01\e[0m \e[0;37mabuela32\e[0m 2Yo3 \e[1;37mabuelo21\e[0m \e[0;32m49hijo1\e[0m \e[0;36m8papa\e[0m \e[0;33m33mama11\e[0m")

for familiar in ${arrayColores[@]}
do
    if [[ $familiar =~ $cafeRegex ]]; then
        echo "Los familiares cafes son: $familiar"
    fi
done
    • 1