Download Sed And Awk 101 Hacks

  • Linux 101 Hacks 2nd Edition eBook - Practical Examples to Build a Strong Foundation in Linux; Bash 101 Hacks eBook - Take Control of Your Bash Command Line and Shell Scripting; Sed and Awk 101 Hacks eBook - Enhance Your UNIX / Linux Life with Sed and Awk; Vim 101 Hacks eBook - Practical Examples for Becoming Fast and Productive in Vim Editor; Nagios Core 3 eBook - Monitor Everything, Be.
  • Sed - UNIX Stream Editor - Cheat Sheet. Here's the next cheat sheet I've created - cheat sheet of sed, the Superman of stream editing. It has come handy 101 times for me because sed is not what I use daily and after some time of not using the sed commands tend to fade away from my mind and I have to review them quickly.
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  2. Sed And Awk 101 Hacks Pdf Download
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Devops007 / Sed-and-Awk-101-Hacks. Sed and Awk 101 hacks. Use Git or checkout with SVN using the web URL. Work fast with our official CLI. If nothing happens, download GitHub Desktop and try again. If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again.

I love cheat-sheets! I love them because they make learning a new programming language, technology or a tool much, much easier.

I wrote the other reasons why I love and use cheat sheets on the first few cheat-sheet posts - awk cheat sheet post and perl's special var post. I don't want to copy paste what I wrote there, so just head to those two articles and read what I have to say about cheat sheets.

Here are all the cheat sheets I have created and I will probably also add the others I am using.

  • Awk, Nawk and Gawk programming language cheat sheetDownload:
  • Sed, Unix Stream Editor cheat sheetDownload:
  • Ed, Unix Interactive Text Editor cheat sheetDownload:
  • Perl programming language's special variable cheat sheetDownload:
  • Perl programming language's pack()/unpack() and printf() cheat sheetDownload:
  • Screen VT100/ANSI terminal emulator keyboard shortcut cheat sheetDownload:
  • Bash (readline) Emacs editing mode cheat sheetDownload:
  • Bash (readline) VI editing mode cheat sheetDownload:
  • Bash history cheat sheetDownload:
  • Set Operations in Unix Shell Cheat SheetDownload:
  • GNU Coreutils Cheat SheetDownload:
  • Util-Linux Cheat SheetDownload:
  • Bash Redirections Cheat SheetDownload:
  • ASCII Cheat SheetDownload:
  • Regular Expression Character Classes Cheat Sheet (Visualization)Download:

If you noticed any inaccuracies in the cheat sheets, please use the feedback form to notify me, or email me, or just post a comment here!

Thanks!

20. Regular Expression Fundamentals‌

PdfHacksRegular expressions (or regex) are used in many *nix commands, including sed.

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Beginning of line ( ^ )

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The Caret Symbol ^ matches at the start of a line.Display lines which start with 103:Note that ^ matches the expression at the beginning of a line, only if it is the first character in a regular expression. In this example, ^N matches all the lines that begins with N.

End of line ( $)

The dollar symbol $ matches the end of a line.Display lines which end with the letter r:

Single Character (.)

The special meta-character “.” (dot) matches any character except the end of the line character.
  • . matches single character
  • .. matches two characters
  • ... matches three characters
  • etc.
In the following example, the pattern 'J followed by three characters and a space' will be replaced with 'Jason followed by a space'. So, 'J... ' matches both 'John ' and 'Jane ' from employee.txt, and these two lines are replaced accordingly as shown below.

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Zero or more Occurrences (*)

The special character “*” (star) matches zero or more occurrences of the previous character. For example, the pattern ’1*’ matches zero or more ’1'.For this example create the following log.txt file:Suppose you would like to view only the lines that contain 'log:' followed by a message. The message might immediately follow the log: or might have some spaces. You don't want to view the lines that contain 'log:' without anything.

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Display all the lines that contain 'log:' followed by one or more spaces followed by a character:Note: In the above example the dot at the end is necessary. If not included, sed will also print all the lines containing 'log:' only.

One or more Occurrence (+)

The special character “+” matches one or more occurrence of the previous character. For example, a space before “+”, i.e ” +” matches at least one or more space character. Let us use the same log.txt as an example file.Display all the lines that contain 'log:' followed by one or more spaces:Note: In addition to not matching the 'log:' only lines, the above example also didn't match the line 'log:output created', as there is no space after 'log:' in this line.

Zero or one Occurrence (?)

The special character “?” matches zero or one occurrences of the previous character as shown below.

Escaping the Special Character ()

If you want to search for special characters (for example: * , dot) in the content you have to escape the special character in the regular expression.

Character Class ([0-9])

The character class is nothing but a list of characters mentioned within a square bracket; this is used to match only one out of several characters.Match any line that contains 2 or 3 or 4:Within the square bracket, you can use a hyphen you can specify a range of characters. For example, [0123456789] can be represented by [0-9], and alphabetic ranges can be specified such as [a-z],[A-Z] etc.Match any line that contains 2 or 3 or 4 (alternate form):

21. Additional Regular Expressions

OR Operation ( )

The pipe character ( ) is used to specify that either of two whole subexpressions could occur in a position. “subexpression1 subexpression2” matches either subexpression1 or subexpression2.Print lines containing either 101 or 102:Please note that the symbol is escaped with a /.Print lines that contain a character from 2 to 3 or that contain the string 105:

Exactly M Occurrences ({m})

A Regular expression followed by {m} matches exactly m occurrences of the preceding expression. For this example create the following numbers.txt file.Print lines that contain any digit (will print all lines):Print lines consisting of exactly 5 digits:

M to N Occurrences ({m,n})

A regular expression followed by {m,n} indicates that the preceding item must match at least m times, but not more than n times. The values of m and n must be non-negative and smaller than 255.Print lines consisting of at least 3 but not more than 5 digits:A Regular expression followed by {m,} is a special case that matches m or more occurrences of the preceding expression.

Word Boundary (b)

b is used to match a word boundary. b matches any character(s) at the beginning (bxx) and/or end (xxb) of a word, thus btheb will find the but not they. bthe will find the or they.Create the following sample file for testing.Match lines containing the whole word 'the':Please note that if you don't specify the b at the end, it will match all lines.Match lines containing words that start with “the”:

Back References (n)

Back references let you group expressions for further use.Match only the line that has the word 'the' repeated twice:Using the same logic, the regular expression '([0-9])1' matches two digit number in which both the digits are same number—like 11,22,33...

22. Sed Substitution Using Regular Expression

The following are few sed substitution examples that uses regular expressions.Replace the last two characters in every line of employee.txt with ',Not Defined':Delete the rest of the line starting from “Manager”:Delete all lines that start with '#' :Create the following test.html for the next example:Strip all html tags from test.html:Remove all comments and blank lines:Remove only the comments. Leave the blank lines:You can convert DOS newlines (CR/LF) to Unix format Using sed. When you copy the DOS file to Unix, you could find rn in the end of each line.Convert the DOS file format to Unix file format using sed: