Awk one-liner to replace text of first matching regex occurence only -


i need awk command replace ss:width="252" in first xml tag in text ss:width="140" , leave rest of tags alone:

cat <<- eof > text     <ss:column ss:autofitwidth="1" ss:width="252"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="252"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="189"/>     <ss:column ss:autofitwidth="1" ss:width="189"/>     <ss:column ss:autofitwidth="1" ss:width="252"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="126"/>     <ss:column ss:autofitwidth="1" ss:width="252"/> eof  awk '{c=++count[$0]} c==1 {sub(/ss:width=\"[0-9]{1,4}\"/,"ss:width=\"140\"")} {print}' text > newf  cat newf

instead, replaces expression in first instances of each of 3 unique matches (three total replacements, whereas want one.)

<ss:column ss:autofitwidth="1" ss:width="140"/> <ss:column ss:autofitwidth="1" ss:width="140"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="252"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="140"/> <ss:column ss:autofitwidth="1" ss:width="189"/> <ss:column ss:autofitwidth="1" ss:width="252"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="126"/> <ss:column ss:autofitwidth="1" ss:width="252"/>

why behave way? how incrementer behaving in awk command? expected increment after first qualifying match of /ss:width=\".*\"/ seems it's not incrementing until unique matches found, ignoring subsequent non-unique matches only. right? tried force counter increment @ end of c == 1 block this:

awk '{c=++count[$0]} c==1 {sub(/ss:width=\".*\"/,"ss:width=\"140\"");c++} {print}' text > newf

but same output. didn't have luck trying task in sed & i'd rather in awk anyway. i'm interested in understanding awk syntax.

edit: tested theory changing 1 of width attributes random number. replace 1 140. so, limiting first instance of matching expressions, not first matching expression itself.

edit: cody pointed out regex greedy. changed .* [0-9]{1,4} behavior same - still replaces first instance of every unique match. changed 1 of xml tags' width attributes 3rd unique number , updated output illustrate behavior i'm trying fix.

this aix/ksh.

awk 'found == 0 { found = sub(/ss:width=\"[0-9]{1,4}\"/,"ss:width=\"140\"")} //' text > newf

you might able shorten bit.

your old approach keeping array of counters indexed line of input. that's why exhibiting behavior weren't expecting.

some of other answers assume lines match /ss:width/ regex and/or find width attribute @ end of line. it's true in case worthy of noting. decided not assume things in script above.


Comments

Post a Comment

Popular posts from this blog

How to connect android app to App engine -

i'm trying connect app in android server i've opened on appengine. my server's name : dddd-daniel-2345 , website server : http://dddd-daniel-2345.appspot.com/ this how connect android app server in app engine: app.yaml: application: dddd-daniel-2345 version: 1 runtime: python27 api_version: 1 threadsafe: yes handlers: - url: .* script: main.app libraries: - name: webapp2 version: "2.5.2" main.py: #!/usr/bin/env python # # copyright 2007 google inc. google.appengine.api import users import webapp2 class userhandler(webapp2.requesthandler): def get(self): user = users.get_current_user() if user: greeting = ('%s,%s,%s' % (user.email(),user.user_id(),user.nickname())) else: greeting = ('not logged in') self.response.out.write(greeting) app = webapp2.wsgiapplication([('/', userhandler),], debug=true) my applications code : add manifast main....
Read more

gcc - MinGW's ld cannot perform PE operations on non PE output file -

i know there other similar questions out there, stackoverflow or not. i've researched lot this, , still didn't find single solution. i'm doing operative system side project. i've been doing in assembly, wanna join c code. test, made assembly code file (called test.asm): [bits 32] global _a section .text _a: jmp $ then made c file (called main.c): extern void a(void); int main(void) { a(); } to link, used file (called make.bat): "c:\mingw\bin\gcc.exe" -ffreestanding -c -o c.o main.c nasm -f coff -o asm.o test.asm "c:\mingw\bin\ld.exe" -ttext 0x100000 --oformat binary -o out.bin c.o asm.o pause i've been researching ages, , i'm still struggling find answer. hope won't flagged duplicate. acknowledge existence of similar questions, have different answers, , none work me. question: what doing wrong? old mingw versions had problem "ld" not able create non-pe files @ all. maybe current versions...
Read more

php - display validation error message next to the textbox in codeigniter -

Image
i'm newbie codeigniter.i want display error message next text box.my view file create.php contains following code. <?php echo validation_errors(); //validation echo form_open('news/create'); //create form ?> <div class="boxes"> <div class="common"> <div class="lables"> <label for="name">name</label> </div> <div class="text_boxes"> <input type="text" name="uname" /><div id="infomessage"><?php echo $message;?></br> </div> </div>` and below controller model: public function create() { $this->load->helper('form'); $this->load->library('form_validation'); $data['title'] = 'insert items'; $this->form_validation->set_rules('uname','required|min_length[6]|m...
Read more