Bash – Replacing a pattern with a string

bashstring

Suppose we declare

test="/this/isjust/atestvariable/for/stringoperation"

and we want to replace each instance of '/' with the colon ':'.

Then, I think this command should work:

echo ${test//\/:}

(as ${variable//pattern/string} replaces all matches of the pattern with the specified string )

But, on running echo ${test//\/:}, I get the output as

/this/isjust/atestvariable/for/stringoperation

Where I could be going wrong? Thank you for your help.

escape slash with backslash

echo ${test//\//:}

You can use pattern matching:

for i in $(drush site-alias) ; do
    if [[ $i == *.* ]] ; then
        drush "$i" command
    fi
done

The syntax error is self-explanatory i.e. you have used ~= instead of =~.

Regarding the Regex pattern, just use $pat (and also $item), being a shell builtin [[ can handle word splitting:

item='foobar baz'
pat=".+bar baz"
if [[ $item =~ $pat ]]; then
    echo ok
fi

When you use double quotes around $pat i.e. "$pat", the Regex tokens . and + are treated literally.

Example:

$ item='foobar baz'; pat=".+bar baz"; if [[ $item =~ $pat ]]; then echo OK; fi
OK