There are a couple of important things to know about bash's [[ ]] construction. The first Double quotes will not protect the special characters properly. If you wanted to match letters, digits or spaces you could use: [[ $x . Browse other questions tagged regex bash if-statement or ask your own question.
You had it right, just put a space between the! and the [[ like if! [[ the safest way is to put the! for the regex negation within the double ] like this: if [[! for this - it can fail if your path contains special characters. Browse other questions tagged regex bash conditional negate or ask your own question.
Questions regular expression finding double characters bash - travelingLearn more about Stack Overflow the company. I'd prefer to use [:punct:] for that. You can also use curly braces to make something optional.
Start here for a quick overview of the site. The following PCRE are supported by:. For example: The -n switch turns off sed's default behavior of printing. In some it's even configurable or depends on switches as in GNU grepwhich you can switch between three different regex dialects. Use of user-defined uppercase variables should be avoided. The following is a list. Sign up or log in to customize your list. Those user asian you who were tearing your hair out in frustration can now stop.
Questions regular expression finding double characters bash - - journey
Thus, as a consequence, raised the secondary issue :.. A lot of the reasoning is historical. Short answer : Yes, the use of backslashes depends on whether one uses grep or egrep.. Backreferences: displays all group in the regular expression in the order in which they were encountered and wheter or not they triggered termination. But beware: In this case, you cannot quote the variable expansion:.. Sign up using Google. The following examples illustrate the syntax and a trivial example: Delete vs Replace with null: If you use the delete feature of sed it deletes the entire line on which 'search expression' appears, which may not be the desired outcome. Yes, -r option is really really helpful for the readability of the expressions.