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![It performs basic text formatting on an input stream ( A file / input from a pipeline ) Formatting using input file $ awk {print $n} Filename Example: $ awk {print $1} awk.txt > awk.txt.bak Formatting using a filter in a pipeline $ generate_data | awk {print $1} Example: $ cat awk.txt | awk {print $1} > awk.txt.bak Before proceeding to next slide please create a file named awk.txt with following Contents. 07.46.199.184 [28/Sep/2010:04:08:20] "GET /robots.txt HTTP/1.1" 200 0 "msnbot" 123.125.71.19 [28/Sep/2010:04:20:11] "GET / HTTP/1.1" 304 - "Baiduspider" Nihar R Paital](https://image.slidesharecdn.com/unix-class7-awk-120626121845-phpapp01/75/Unix-Class7-awk-4-2048.jpg)
![Advance use of AWK $ awk '{print $2}' logs.txt Output: [28/Sep/2010:04:08:20] [28/Sep/2010:04:20:11] The date field is separated by "/" and ":" characters. Suppose I want to print like [28/Sep/2010 [28/Sep/2010 $ awk '{print $2}' logs.txt | awk 'BEGIN{FS=":"}{print $1}' Output: [28/Sep/2010 [28/Sep/2010 Here FS=“:” means Field Separator as colon(:) $ awk '{print $2}' logs.txt | awk 'BEGIN{FS=":"}{print $1}' | sed 's/[//' Output: 28/Sep/2010 28/Sep/2010 Here We are Substituting [ with NULL value Nihar R Paital](https://image.slidesharecdn.com/unix-class7-awk-120626121845-phpapp01/75/Unix-Class7-awk-7-2048.jpg)
![Advance Use of AWK If I want to return only the 200 status lines $ awk '{if ($(NF-2) == "200") {print $0}}' logs.txt Output: 07.46.199.184 [28/Sep/2010:04:08:20] "GET /robots.txt HTTP/1.1" 200 0 "msnbot" $ awk '{a+=$(NF-2); print "Total so far:", a}' logs.txt Output: Total so far: 200 Total so far: 504 $ awk '{a+=$(NF-2)}END{print "Total:", a}' logs.txt Output: Total: 504 Nihar R Paital](https://image.slidesharecdn.com/unix-class7-awk-120626121845-phpapp01/75/Unix-Class7-awk-8-2048.jpg)
Uploaded byNihar Ranjan Paital
Unix - Class7 - awk
Awk is a data extraction and reporting tool developed in the 1970s at Bell Labs to perform basic text formatting on input streams and files, using a scripting language to take actions on textual data and produce formatted reports. It parses input into fields separated by whitespace that can then be accessed and manipulated through variables like $1, $2, NF, and NR to extract and report on specific fields. Advanced uses include conditioning printing on field values, manipulating field values through pipes and sed, and accumulating calculations with variables over the entire file.
Unix - Class7 - awk
- 1. UNIX - awk Data extraction and formatted Reporting Tool Presentation By Nihar R Paital
- 2. Introduction Developer : Alfred Aho Peter Weinberger Brian Kernighan Appears in : Version 7 UNIX onwards Developed during : 1970 s Developed at : Bell Labs Category : UNIX Utility Supported by : All UNIX flavors Nihar R Paital
- 3. Definition The AWKutility is a data extraction and reporting tool that uses a data-driven scripting language consisting of a set of actions to be taken against textual data (either in files or data streams) for the purpose of producing formatted reports. Nihar R Paital
- 4. It performs basictext formatting on an input stream ( A file / input from a pipeline ) Formatting using input file $ awk {print $n} Filename Example: $ awk {print $1} awk.txt > awk.txt.bak Formatting using a filter in a pipeline $ generate_data | awk {print $1} Example: $ cat awk.txt | awk {print $1} > awk.txt.bak Before proceeding to next slide please create a file named awk.txt with following Contents. 07.46.199.184 [28/Sep/2010:04:08:20] "GET /robots.txt HTTP/1.1" 200 0 "msnbot" 123.125.71.19 [28/Sep/2010:04:20:11] "GET / HTTP/1.1" 304 - "Baiduspider" Nihar R Paital
- 5. Basic but importantfor awk Syntax : awk {print $n} filename Generate data : awk {print $n} Awk programs will start with a "{" and end with a "}" $0 is the entire line Awk parses the line in to fields for you automatically, using any whitespace (space, tab) as a delimiter. Fields of a regular file will be available using $1,$2,$3 … etc NF : It is a special Variable contains the number of fields in the current line. We can print the last field by printing the field $NF NR : It prints the row number being currently processed. Nihar R Paital
- 6. Basic Examples $awk '{print $0}' awk.txt It will print all the lines as they are in File $ echo 'this is a test' | awk '{print $3}' It will print 'a' $ echo 'this is a test' | awk '{print $NF}' It prints "test" $ awk '{print $1, $(NF-2) }' awk.txt It will print the last 3rd word of file awk.txt $ awk '{print NR ") " $1 " -> " $(NF-2)}‘ Output: 1) 07.46.199.184 -> 200 2) 123.125.71.19 -> 304 Nihar R Paital
- 7. Advance use ofAWK $ awk '{print $2}' logs.txt Output: [28/Sep/2010:04:08:20] [28/Sep/2010:04:20:11] The date field is separated by "/" and ":" characters. Suppose I want to print like [28/Sep/2010 [28/Sep/2010 $ awk '{print $2}' logs.txt | awk 'BEGIN{FS=":"}{print $1}' Output: [28/Sep/2010 [28/Sep/2010 Here FS=“:” means Field Separator as colon(:) $ awk '{print $2}' logs.txt | awk 'BEGIN{FS=":"}{print $1}' | sed 's/[//' Output: 28/Sep/2010 28/Sep/2010 Here We are Substituting [ with NULL value Nihar R Paital
- 8. Advance Use ofAWK If I want to return only the 200 status lines $ awk '{if ($(NF-2) == "200") {print $0}}' logs.txt Output: 07.46.199.184 [28/Sep/2010:04:08:20] "GET /robots.txt HTTP/1.1" 200 0 "msnbot" $ awk '{a+=$(NF-2); print "Total so far:", a}' logs.txt Output: Total so far: 200 Total so far: 504 $ awk '{a+=$(NF-2)}END{print "Total:", a}' logs.txt Output: Total: 504 Nihar R Paital
- 9.