Category: Csplit examples regular expression

Csplit examples regular expression

Below, you will find many example patterns that you can use for and adapt to your own purposes. Key techniques used in crafting each regex are explained, with links to the corresponding pages in the tutorial where these concepts and techniques are explained in great detail. If you are new to regular expressions, you can take a look at these examples to see what is possible.

Regular expressions are very powerful. They do take some time to learn. But you will earn back that time quickly when using regular expressions to automate searching or editing tasks in EditPad Pro or PowerGREPor when writing scripts or applications in a variety of languages. RegexBuddy offers the fastest way to get up to speed with regular expressions. RegexBuddy will analyze any regular expression and present it to you in a clearly to understand, detailed outline.

Anything between the tags is captured into the first backreference. The question mark in the regex makes the star lazyto make sure it stops before the first closing tag rather than before the last, like a greedy star would do. Be sure to turn off case sensitivity.

Anything between the tags is captured into the second backreference. This solution will also not match tags nested in themselves. You can easily trim unnecessary whitespace from the start and the end of a string or the lines in a text file by doing a regex search-and-replace.

csplit examples regular expression

Numeric Ranges. Since regular expressions work with text rather than numbers, matching specific numeric ranges requires a bit of extra care. Matching a Floating Point Number. Also illustrates the common mistake of making everything in a regular expression optional. Matching an Email Address.

Advanced regular expressions usage with real world example

Matching Valid Dates. A regular expression that matches but not Finding or Verifying Credit Card Numbers. Validate credit card numbers entered on your order form. Find credit card numbers in documents for a security audit. Matching Complete Lines. Shows how to match complete lines in a text file rather than just the part of the line that satisfies a certain requirement.

Also shows how to match lines in which a particular regex does not match. Removing Duplicate Lines or Items. Illustrates simple yet clever use of capturing parentheses or backreferences. Regex Examples for Processing Source Code. How to match common programming language syntax such as comments, strings, numbers, etc. Two Words Near Each Other. Catastrophic Backtracking.

If your regular expression seems to take forever, or simply crashes your application, it has likely contracted a case of catastrophic backtracking.

Making Everything Optional. If all the parts in your regex are optional, it will match a zero-length string anywhere.

Sample Regular Expressions

Your regex will need to express the facts that different parts are optional depending on which parts are present. Repeating a Capturing Group vs.

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Capturing a Repeated Group. Repeating a capturing group will capture only the last iteration of the group.It only takes a minute to sign up.

I have a text file which I want to split into 64 unequal parts, according to the 64 hexagrams of the Yi Jing. Since the passage for each hexagram begins with some digit sa period, and two newlines, the regex should be pretty easy to write.

But how do I actually split the text file into 64 new files according to this regex? It seems like more of a task for perl. But maybe there's a more obvious way that I'm just totally missing.

This would be csplit except that the regex has to be a single line. That also makes sed difficult; I'd go with Perl or Python. It is a regex, here we use multiple seperators: ".

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Thus a line like 1. The value x will be used as file name for print operation. With GNU coreutils, you can use csplit to break a file into regexp-delimited pieces, as shown by geekosaur. On MacOS, split has a -p parameter that takes a regexp. Each time split encounters a line matching the regexp, a new output file is opened, starting with that line.

IF your reason for splitting is to process each block with a different command, GNU Parallel may be the tool of choice:.

Sign up to join this community. The best answers are voted up and rise to the top. Splitting text files based on a regular expression Ask Question.

Asked 9 years, 7 months ago. Active 8 months ago. Viewed 25k times. Improve this question. Add a comment. Active Oldest Votes. You could see if csplit foo. Improve this answer. Thanks, geekosaur. I think the best way is awk and gawk. Wang Wang 1 1 gold badge 8 8 silver badges 16 16 bronze badges. Here's a portable awk script to break a file into pieces. It works by calling getline to deal with the multiline 2-line separator; setting a variable outfile to the name of the file to print to, when a section header is encountered.

Gilles 'SO- stop being evil' Gilles 'SO- stop being evil' k gold badges silver badges bronze badges. This works in principlebut the section-header of the actual web page data is not as represented by the regex likewise with geekosaur's answer.

The leading nunber. O Jun 27 '11 at The layout will depend on the HTML rendering engine used to convert to text; the part where this is rendered from a web page is actually irrelevant to the question.

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It's not going to occur here, but I support it in my code to make it more general and match the specification in the question more strictly. Law29 Law29 1 1 gold badge 8 8 silver badges 16 16 bronze badges. Ole Tange Ole Tange 25k 21 21 gold badges 75 75 silver badges bronze badges.By default, 'csplit' prints the number of bytes written to each output file after it has been created.

The output files' names consist of a prefix 'xx' by default followed by a suffix. By default, the suffix is an ascending sequence of two-digit decimal numbers from '00' and up to '99'. In any case, concatenating the output files in sorted order by filename produces the original input file. By default, if 'csplit' encounters an error or receives a hangup, interrupt, quit, or terminate signal, it removes any output files that it has created so far before it exits.

Previous Page. Next Page. Previous Page Print Page. Dashboard Logout. When this option is specified, the suffix string must include exactly one 'printf 3 '-style conversion specification, possibly including format specification flags, a field width, a precision specifications, or all of these kinds of modifiers. The format letter must convert a binary integer argument to readable form; thus, only 'd', 'i', 'u', 'o', 'x', and 'X' conversions are allowed. The entire SUFFIX is given with the current output file number to 'sprintf 3 ' to form the file name suffixes for each of the individual output files in turn.

If this option is used, the '--digits' option is ignored. Suppress the generation of zero-length output files. In cases where the section delimiters of the input file are supposed to mark the first lines of each of the sections, the first output file will generally be a zero-length file unless you use this option.

The output file sequence numbers always run consecutively starting from 0, even when this option is specified. Create an output file containing the input up to but not including line N a positive integer. If followed by a repeat count, also create an output file containing the next LINE lines of the input file once for each repeat.

Create an output file containing the current line up to but not including the next line of the input file that contains a match for REGEXP.

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If it is given, the input up to the matching line plus or minus OFFSET is put into the output file, and the line after that begins the next section of input. Like the previous type, except that it does not create an output file, so that section of the input file is effectively ignored.Post a Comment. The command "csplit" can be used to split a file into different files based on certain pattern in the file or line numbers.

For example let us say we have the file, temp, with the following contents temp: Line one Line two Line three Line four Line five Line six Line seven Line eight we can split the file into two new files ,each having part of the contents of the original file, using csplit.

The syntax of csplit is csplit [options] file PATTERN Pattern as integer number: When the pattern is an integer number it makes cplit to copy line upto that line number,no including the line, into a new file and contents after that into a new file. After the execution of the command we can see that we have two new files "xx00" and "xx01", these are the files created by csplit.

The names of the new files created are by default of the format "xx00", "xx01" Pattern as a Regular expression: We can also pass regular expressions as patterns to split the file. Thus the file was split 7 times with one line in each file. Posted by tuxthink Email This BlogThis! No comments:. Newer Post Older Post Home.

Subscribe to: Post Comments Atom. Follow by Email.For example, you can use csplit to break up a text file into chunks of ten lines each, then save each of those chunks in a separate file. See the subsection Splitting Criteria for more details. If you specify - as the file argument, csplit uses the standard input. This generates names of the form xxAAxxABand so on. This generates names of the form xxaaxxaband so on.

Normally, when an error occurs, csplit removes files that it has created. The first argument breaks off the first chunk of the file, the second argument breaks off the next chunk beginning at the first line remaining in the file and so on.

Thus each chunk of the file begins with the first line remaining in the file and goes to the line given by the next arg.

After csplit has obtained the chunk and written it to an output file, it sets the current line to the line that matched regexp. The offset may be a positive or negative integer. It simply skips over the chunk. After csplit writes the chunk to an output file, it sets the current line to linenumber. If it follows a regular expression criterion, it repeats the regular expression process number more times.

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If it follows a linenumber criterion, csplit splits the file every linenumber lines, number times, beginning at the current line. For example. Errors occur if any criterion tries to grab lines beyond the end of the file, if a regular expression does not match any line between the current line and the end of the file, or if an offset refers to a position before the current line or past the end of the file.

All UNIX systems. Windows Server Windows 8. Windows Server R2.

csplit examples regular expression

Windows Commands: awksed. Miscellaneous: regexp. The files created by csplit normally have names of the form xx number where number is a two digit decimal number which begins at zero and increments by one for each new file that csplit creates.The csplit utility reads the file named by the file operand, writes all or part of that file into other files as directed by the arg operands, and writes the sizes of the files.

Names the created files prefix 00prefix 01The default is xx If the prefix argument would create a file name exceeding 14 bytes, an error results. In that case, csplit exits with a diagnostic message and no files are created. Leaves previously created files intact. By default, csplit removes created files if an error occurs. Uses number decimal digits to form filenames for the file pieces. The default is 2. The path name of a text file to be split. If file is -the standard input will be used.

Create a file using the content of the lines from the current line up to, but not including, the line that results from the evaluation of the regular expression with offsetif any, applied. The regular expression rexp must follow the rules for basic regular expressions. The optional offset must be a positive or negative integer value representing a number of lines. If the selection of lines from an offset expression of this type would create a file with zero lines, or one with greater than the number of lines left in the input file, the results are unspecified.

After the section is created, the current line will be set to the line that results from the evaluation of the regular expression with any offset applied. The pattern match of rexp always is applied from the current line to the end of the file. Lines in the file will be numbered starting at one. Repeat operand. This operand can follow any of the operands described previously.

If it follows a rexp type operand, that operand will be applied num more times. An error will be reported if an operand does not reference a line between the current position and the end of the file.

See largefile 5 for the description of the behavior of csplit when encountering files greater than or equal to 2 Gbyte 2 31 bytes. This example splits the file at every lines, up to 10, lines. The -k option causes the created files to be retained if there are less than 10, lines; however, an error message would still be printed. If prog. See attributes 5 for descriptions of the following attributes:.

The given argument did not reference a line between the current position and the end of the file. Search Scope:. Options The following options are supported: -f prefix Names the created files prefix 00prefix 01Operands The following operands are supported: file The path name of a text file to be split. The operands arg Usage See largefile 5 for the description of the behavior of csplit when encountering files greater than or equal to 2 Gbyte 2 31 bytes.

Exit Status The following exit values are returned: 0 Successful completion.The csplit utility reads the file named by the file operand, writes all or part of that file into other files as directed by the arg operands, and writes the sizes of the files. Names the created files prefix 00prefix 01The default is xx If the prefix argument would create a file name exceeding 14 bytes, an error results.

In that case, csplit exits with a diagnostic message and no files are created. Leaves previously created files intact. By default, csplit removes created files if an error occurs.

Uses number decimal digits to form filenames for the file pieces. The default is 2.

how to get the example file:

The path name of a text file to be split. If file is -the standard input will be used. Create a file using the content of the lines from the current line up to, but not including, the line that results from the evaluation of the regular expression with offsetif any, applied. The regular expression rexp must follow the rules for basic regular expressions. The optional offset must be a positive or negative integer value representing a number of lines.

If the selection of lines from an offset expression of this type would create a file with zero lines, or one with greater than the number of lines left in the input file, the results are unspecified.

After the section is created, the current line will be set to the line that results from the evaluation of the regular expression with any offset applied. The pattern match of rexp always is applied from the current line to the end of the file.

Lines in the file will be numbered starting at one. Repeat operand. This operand can follow any of the operands described previously. If it follows a rexp type operand, that operand will be applied num more times. An error will be reported if an operand does not reference a line between the current position and the end of the file.

See largefile 5 for the description of the behavior of csplit when encountering files greater than or equal to 2 Gbyte 2 31 bytes. This example splits the file at every lines, up to 10, lines.

The -k option causes the created files to be retained if there are less than 10, lines; however, an error message would still be printed. If prog.

csplit examples regular expression

See attributes 5 for descriptions of the following attributes:. The given argument did not reference a line between the current position and the end of the file. Options The following options are supported: -f prefix Names the created files prefix 00prefix 01Operands The following operands are supported: file The path name of a text file to be split.

The operands arg Usage See largefile 5 for the description of the behavior of csplit when encountering files greater than or equal to 2 Gbyte 2 31 bytes.

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