Grep find and replace recursive relationship

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grep find and replace recursive relationship

Hi, If you want to search and replace specific string from multiple file recursively then below command is useful for it: Linux Command. files package require fileutil proc is_tcl {name} {return [string match *.tcl $ name]} set except that it doesn't allow recursion over more than one directory at a time. ::fileutil::grep pattern?files? If -m, only change the mtime. the command is not able to compute this relationship between the arguments if one of the. cd /path-to-dir ## change directories to the root directory that you find command searches for files in a directory hierarchy recursively by default. Or combine the two commands into a single command: find /path-to-dir -name "*. html" -exec grep -l '' {} + . Is this co-worker relationship salvageable?.

So now you should have at least a basic grasp of how regexes work in practice. The rest of this chapter gives more examples and explains some of the more powerful topics, such as capture groups. As for how regexes work in theory—and there is a lot of theoretical details and differences among regex flavors—the interested reader is referred to the book Mastering Regular Expressions. Using regexes in Java: If all you need is to find out whether a given regex matches a string, you can use the convenient boolean matches method of the String class, which accepts a regex pattern in String form as its argument: If the regex is going to be used more than once or twice in a program, it is more efficient to construct and use a Pattern and its Matcher s.

A complete program constructing a Pattern and using it to match is shown here: It is on time. The normal steps for regex matching in a production program are: Create a Pattern by calling the static method Pattern. Request a Matcher from the pattern by calling pattern. Call once or more one of the finder methods discussed later in this section in the resulting Matcher.

How to do max-depth search in ack and grep? - Unix & Linux Stack Exchange

CharSequence interface provides simple read-only access to objects containing a collection of characters. Of course, you can perform regex matching in other ways, such as using the convenience methods in Pattern or even in java. As well, the Matcher has several finder methods, which provide more flexibility than the String convenience routine match. The Matcher methods are: Since it matches the entire String, I had to put.

grep find and replace recursive relationship

Each of these methods returns boolean, with true meaning a match and false meaning no match. To check whether a given string matches a given pattern, you need only type something like the following: The following recipes cover uses of this API. Initially, the examples just use arguments of type String as the input source.

Finding the Matching Text You need to find the text that the regex matched. Solution Sometimes you need to know more than just whether a regex matched a string.

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In editors and many other tools, you want to know exactly what characters were matched. Do not underestimate the mighty. There are ways to get the same results using an even shorter query, but in most cases, it pays to break up your jq transformations into small steps. All we need to do is construct the CSV row arrays and pipe them through the csv operator: Grouping and Counting Often times, your JSON will be structured around one type of entity say, artworks from the Rijksmuseum API, or tweets from the Twitter API when you, the researcher, may be more interested in collecting information about a related, but secondary entity, like an artist, a Twitter hashtag, or a Twitter user.

In this section, we will use jq to extract a table of information about Twitter users from the tweet-based JSON, as well as grouping and counting tweet hashtags.

For the previous examples, we have only needed to consider each tweet individually. By default, jq will look at one JSON object at a time when parsing a file; consequently, it can stream very large files without having to load the entire set in to memory. However, in cases where we are aggregating information about the individual objects in a JSON file, we need to give jq access to every JSON object in a file simultaneously.

Now we can build even more complex commands that require knowledge of the entire input file. Extracting user data Because the Twitter API returns per-tweet information, info about the users who send those tweets is repeated with each tweet within an object assigned to the key user.

The results will look like this: How do we do that? The command tostring converts the tweet id numbers into strings that jq can then paste together with semicolons.

grep find and replace recursive relationship

Because when we were making a column of hashtags, the original values were already text values wrapped in quotation marks. Tweet ids, on the other hand, are integers that are not wrapped in "", Because jq can be very picky about data types, we need to convert our integers into strings before using the join command in the next step.

grep find and replace recursive relationship

Both of these commands are wrapped in [] which tells jq to collect every result into one single array, which is passed with a along to: This filter created new JSON. To produce a CSV table from this, we just need to add an array construction and the csv command at the end of this filter. You should recognize the way that we combine array construction and csv from the earlier example of using csv. Although this table happens to start with users who only have one tweet each in these sample data, you can scroll down through the results to find several users who made multiple tweets.

In this final exercise, we will use jq to count the number of times unique hashtags appear in this dataset. Counterintuitively, the first thing we need to do to access the hashtags again is to break them out of that large array: This is necessary because, while tweets can only have one user, they can have multiple hashtags. We did a similar sort of wrapping in the previous section of this lesson. To count the number of times each hashtag is used, we only have to count the size of each of these sub-arrays.

We need to retrieve two pieces of information: Second, we need to get the length of the array, accessed with. Filter before counting What function do we need to add to the hashtag-counting filter to only count hashtags when their tweet has been retweeted at least times? You should get the following table: See my answer here.

grep find and replace recursive relationship

Count total retweets per user One more challenge to test your mastery of jq: You should have a table with two columns: There should only be one row per user id. If you want to add numeric values together, though, add could be a promising function to try… As a way to verify your results, user should have a total retweet count of 51 based on this dataset.

Reshaping JSON with jq | Programming Historian

Using jq on the command line jq play is fine when you have under lines of JSON to parse. However, it will become unusably slow on much larger files.

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For fast processing of very large files, or of JSON lines spread across multiple files, you will need to run the command-line version of jq. Follow the installation instructions for Homebrew itself, and then use this command to install jq: The actual filter text is placed between '' quotes.

For anything serious, you probably don't want to use them. However, their syntax makes them useful for simple parsing or text manipulation problems that crop up on the command line.

Writing a simple line of awk can be faster and less hassle than hauling out Perl or Python. The key point about awk is, it works line by line. A typical awk construction is: Let's say we have a file, test.

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If you define variables in awk they're global and persist rather than being cleared every line. For example, we can concatenate the elements of the first column with an delimiter using the variable x: There are many more you can read about here. Continuing with our very contrived examples, let's see how these can help us: We can just use a comma instead. Look at the following three examples: The second command prints the file with the row number added in front.