bill@twg.bc.ca (Bill Irwin) (10/29/90)
I have what initially seemed to be a simple requirement: get the first
two fields from each line in file_1, and use them as a search pattern for
GREP to extract matching lines in file_2. Sounds simple doesn't it? Not
for someone with very limited knowledge of AWK! The first pass at this
was:
for x in `cat file_1 | awk '{ print $1 " " $2 }'`
do
grep "$x" file_2
done
Of course, the GREP routine executed with x having the value of the first
field of the first line of file_1, then with the value of the second
field of the first line of file_1, then the first field of the second
line, .....
Is there a way to get AWK to output "field_1 field_2" as the value of x,
so that this can be used as the search pattern for GREP, rather than
"field_1" "field_2" "field_1" "field_2"?
--
Bill Irwin - The Westrheim Group - Vancouver, BC, Canada
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
uunet!van-bc!twg!bill (604) 431-9600 (voice) | UNIX Systems
bill@twg.bc.ca (604) 430-4329 (fax) | Integrationjak9213@helios.TAMU.EDU (John Kane) (10/29/90)
In article <297@twg.bc.ca> bill@twg.bc.ca (Bill Irwin) writes: >I have what initially seemed to be a simple requirement: get the first >two fields from each line in file_1, and use them as a search pattern for >GREP to extract matching lines in file_2. [...] >for x in `cat file_1 | awk '{ print $1 " " $2 }'` >do > grep "$x" file_2 >done >Of course, the GREP routine executed with x having the value of the first >field of the first line of file_1, then with the value of the second >field of the first line of file_1, then the first field of the second >line, ..... >Is there a way to get AWK to output "field_1 field_2" as the value of x, >so that this can be used as the search pattern for GREP, rather than >"field_1" "field_2" "field_1" "field_2"? Yep, There is. for x in `cat file_1 | awk '{print "\"" $1 " " $2 "\"")'` do grep "$x" file_2 done Your problem was that you were just putting out the values as: field_1 field_2 By putting in the "\"" you are now getting: "field_1 field_2" Hopefully this is what you need. BTW, you can also do it: awk '{ print "grep \"" $1 " " $2 "\" file_2" }' | sh This outputs lines like: grep "field_1 field_2" file_2 etc ... I like to do it this way instead of the other, unless I need to do something else with the "field_1 field_2" arguments, in addition to the grep. -- John Arthur Kane, Systems Analyst, Microcomputer Support and Training Texas A&M University, College Station, TX 77843 (409) 845-9999 jak9213@helios.tamu.edu profs: x043jk@tamvm1.tamu.edu
ronald@atcmp.nl (Ronald Pikkert) (10/29/90)
From article <297@twg.bc.ca>, by bill@twg.bc.ca (Bill Irwin):
<>
<> Is there a way to get AWK to output "field_1 field_2" as the value of x,
<> so that this can be used as the search pattern for GREP, rather than
<> "field_1" "field_2" "field_1" "field_2"?
Your problem comes up AFTER awk. The for loop that you use
considers spaces to be field seperators and awk outputs spaces
on your request.
You could do this:
cat file_1 | awk '{ print $1 " " $2 }' | while read x
do
grep "$x" file_2
done
The read statement will leave the spaces in the awk output
unchanged.
-
Ronald Pikkert E-mail: ronald@atcmp.nl
@ AT Computing b.v. Tel: 080 - 566880
Toernooiveld
6525 ED Nijmegenitkin@mrspoc.Transact.COM (Steven M. List) (10/30/90)
jak9213@helios.TAMU.EDU (John Kane) writes: >In article <297@twg.bc.ca> bill@twg.bc.ca (Bill Irwin) writes: >>I have what initially seemed to be a simple requirement: get the first >>two fields from each line in file_1, and use them as a search pattern for >>GREP to extract matching lines in file_2. [...] >>for x in `cat file_1 | awk '{ print $1 " " $2 }'` >>do >> grep "$x" file_2 >>done >>Of course, the GREP routine executed with x having the value of the first >>field of the first line of file_1, then with the value of the second >>field of the first line of file_1, then the first field of the second >>line, ..... >>Is there a way to get AWK to output "field_1 field_2" as the value of x, >>so that this can be used as the search pattern for GREP, rather than >>"field_1" "field_2" "field_1" "field_2"? >Yep, There is. >for x in `cat file_1 | awk '{print "\"" $1 " " $2 "\"")'` >do > grep "$x" file_2 >done This seems a bit complicated, doesn't it? How about: for x in "`cat file_1 | awk '{print $1, $2}'`" do grep "$x" file_2 done That is, why worry about the backslashes and quotes INSIDE AWK, when you can put them outside? Clean and simple! -- +----------------------------------------------------------------------------+ : Steven List @ Transact Software, Inc. :^>~ : : Chairman, Unify User Group of Northern California : : {apple,coherent,limbo,mips,pyramid,ubvax}!itkin@guinan.Transact.COM :
engbert@cs.vu.nl (Engbert Gerrit IJff) (11/01/90)
In article <1990Oct29.171816.7459@mrspoc.Transact.COM>, itkin@mrspoc.Transact.COM (Steven M. List) writes: ) jak9213@helios.TAMU.EDU (John Kane) writes: ) ) >In article <297@twg.bc.ca> bill@twg.bc.ca (Bill Irwin) writes: ) >>I have what initially seemed to be a simple requirement: get the first ) >>two fields from each line in file_1, and use them as a search pattern for ) >>GREP to extract matching lines in file_2. [...] ) ) >>for x in `cat file_1 | awk '{ print $1 " " $2 }'` ) >>do ) >> grep "$x" file_2 ) >>done ) ) >>Of course, the GREP routine executed with x having the value of the first ) >>field of the first line of file_1, then with the value of the second ) >>field of the first line of file_1, then the first field of the second ) >>line, ..... ) ) >>Is there a way to get AWK to output "field_1 field_2" as the value of x, ) >>so that this can be used as the search pattern for GREP, rather than ) >>"field_1" "field_2" "field_1" "field_2"? ) ) >Yep, There is. ) ) >for x in `cat file_1 | awk '{print "\"" $1 " " $2 "\"")'` ) >do ) > grep "$x" file_2 ) >done ) ) This seems a bit complicated, doesn't it? How about: ) ) for x in "`cat file_1 | awk '{print $1, $2}'`" ) do ) grep "$x" file_2 ) done ) ) That is, why worry about the backslashes and quotes INSIDE AWK, when you ) can put them outside? Clean and simple! ) -- IMHO you will only get one x containing the whole awk output and an this will cause the error message grep: illegal regular expression: No remembered search string. However, using fgrep in your simple example works fine, provided the whole construct is NOT meant to search for regular expressions. Bert.
lugnut@sequent.UUCP (Don Bolton) (11/14/90)
In article <1990Oct29.171816.7459@mrspoc.Transact.COM> itkin@guinan.Transact.COM writes: >jak9213@helios.TAMU.EDU (John Kane) writes: > >>In article <297@twg.bc.ca> bill@twg.bc.ca (Bill Irwin) writes: >>>I have what initially seemed to be a simple requirement: get the first >>>two fields from each line in file_1, and use them as a search pattern for >>>GREP to extract matching lines in file_2. [...] > >>>for x in `cat file_1 | awk '{ print $1 " " $2 }'` >>>do >>> grep "$x" file_2 >>>done > >>>Of course, the GREP routine executed with x having the value of the first >>>field of the first line of file_1, then with the value of the second >>>field of the first line of file_1, then the first field of the second >>>line, ..... > >>>Is there a way to get AWK to output "field_1 field_2" as the value of x, >>>so that this can be used as the search pattern for GREP, rather than >>>"field_1" "field_2" "field_1" "field_2"? > >>Yep, There is. > >>for x in `cat file_1 | awk '{print "\"" $1 " " $2 "\"")'` >>do >> grep "$x" file_2 >>done > >This seems a bit complicated, doesn't it? How about: > > for x in "`cat file_1 | awk '{print $1, $2}'`" > do > grep "$x" file_2 > done > >That is, why worry about the backslashes and quotes INSIDE AWK, when you >can put them outside? Clean and simple! except the for statement still loops for EACH argument retrieved by your awk statement. SOOOO... try #Place in a _ to join $1 and $2 so the for loop sees a single arg for x in `cat file_1 | awk '{print $1"_"$2}'` do #Using the -F option for awk, remove the joiner for use by grep blarg=`echo $x | awk -F_ '{print $1, $2}'` grep $blarg file_2 done Now you'll get what you want
lugnut@sequent.UUCP (Don Bolton) (11/14/90)
In article <46366@sequent.UUCP> lugnut@sequent.UUCP (Don Bolton) Will live to regret writing :-) >In article <1990Oct29.171816.7459@mrspoc.Transact.COM> itkin@guinan.Transact.COM writes: >>jak9213@helios.TAMU.EDU (John Kane) writes: >> >>>In article <297@twg.bc.ca> bill@twg.bc.ca (Bill Irwin) writes: >>>>I have what initially seemed to be a simple requirement: get the first >>>>two fields from each line in file_1, and use them as a search pattern for >>>>GREP to extract matching lines in file_2. [...] >> >>>>for x in `cat file_1 | awk '{ print $1 " " $2 }'` >>>>do >>>> grep "$x" file_2 >>>>done >> >>>>Of course, the GREP routine executed with x having the value of the first >>>>field of the first line of file_1, then with the value of the second >>>>field of the first line of file_1, then the first field of the second >>>>line, ..... >> >>>>Is there a way to get AWK to output "field_1 field_2" as the value of x, >>>>so that this can be used as the search pattern for GREP, rather than >>>>"field_1" "field_2" "field_1" "field_2"? >> >>>Yep, There is. >> >>>for x in `cat file_1 | awk '{print "\"" $1 " " $2 "\"")'` >>>do >>> grep "$x" file_2 >>>done >> >>This seems a bit complicated, doesn't it? How about: >> >> for x in "`cat file_1 | awk '{print $1, $2}'`" >> do >> grep "$x" file_2 >> done >> >>That is, why worry about the backslashes and quotes INSIDE AWK, when you >>can put them outside? Clean and simple! > >except the for statement still loops for EACH argument retrieved by your >awk statement. SOOOO... try OK I'm blind, missed the external " "s that you even mentioned. I hate it when that happens. So SHOOT ME NOW <BOOM> >#Place in a _ to join $1 and $2 so the for loop sees a single arg > >for x in `cat file_1 | awk '{print $1"_"$2}'` > do > >#Using the -F option for awk, remove the joiner for use by grep > > blarg=`echo $x | awk -F_ '{print $1, $2}'` > grep $blarg file_2 > done > >Now you'll get what you want Must be time for lunch. certainly out to it anyways :-)