Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Match text to lines in a file, iterate backwards until text or text substring matches, print to file
Top Forums Shell Programming and Scripting Match text to lines in a file, iterate backwards until text or text substring matches, print to file Post 303038582 by MadeInGermany on Friday 6th of September 2019 01:36:12 PM
Old 09-06-2019
A shell script that works as I described:
Code:
#!/bin/sh
# read from f1, print in this order
while read f1line
do
  # read from f2, find matches => print
  while IFS="," read f2col1 f2othercols
  do
    case $f1line in
    ("$f2col1"*)
      echo "$f1line,$f2col1,$f2othercols"
    esac
  done < file2.txt
done < file1.txt

The same idea in awk (file2 is read into an array variable first):
Code:
#!/bin/sh
awk -F"," '
{
  if (NR==FNR) {
  # read from f2 into associative array col1[]
    col1[$1]=($2 FS $3)
  } else {
  # read from f1, find matches => print
    for (c in col1)
      if (c == substr($0,1,length(c)))
        print $0 FS c FS col1[c]
  }  
}
' file2.txt file1.txt

In awk your propsed way can be implemented with no big overhead:
Code:
#!/bin/sh
awk -F"," '
{
  if (NR==FNR) {
  # read from f2 into associative array col1[]
    col1[$1]=($2 FS $3)
  } else {
  # read from f1, find matches => print
  for (i=length; i>=1; i--)
    if ((c=substr($0,1,i)) in col1)
      print $0 FS c FS col1[c]
  }  
}
' file2.txt file1.txt

 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Print only certain lines from a text file

Hi all, I have a text file and I want to clean up the file by only print those lines start with the date. Is there anyway I can do that?  Thanks CT (1 Reply)
Discussion started by: CamTu
1 Replies

2. Shell Programming and Scripting

Search text from a file and print text and one previous line too

Hi, Please let me know how to find text and print text and its previous line. Please don't get irritated few days back I asked text and next line. I am using HP-UX 11.11 Thanks for your help. (6 Replies)
Discussion started by: kamranjalal
6 Replies

3. Shell Programming and Scripting

[bash help]Adding multiple lines of text into a specific spot into a text file

I am attempting to insert multiple lines of text into a specific place in a text file based on the lines above or below it. For example, Here is a portion of a zone file. IN NS ns1.domain.tld. IN NS ns2.domain.tld. IN ... (2 Replies)
Discussion started by: cdn_humbucker
2 Replies

4. UNIX for Dummies Questions & Answers

Extracting lines from a text file based on another text file with line numbers

Hi, I am trying to extract lines from a text file given a text file containing line numbers to be extracted from the first file. How do I go about doing this? Thanks! (1 Reply)
Discussion started by: evelibertine
1 Replies

5. Shell Programming and Scripting

How to delete lines of a text file based on another text file?

I have 2 TXT files with with 8 columns in them(tab separated). First file has 2000 entries whereas 2nd file has 300 entries. The first file has ALL the lines of second file. Now I need to remove those 300 lines (which are in both files) from first file so that first file's line count become... (2 Replies)
Discussion started by: prvnrk
2 Replies

6. Shell Programming and Scripting

Read n lines from a text files getting n from within the text file

I dont even have a sample script cause I dont know where to start from. My data lookes like this > sat#16 #data: 15 site:UNZA baseline: 205.9151 0.008 -165.2465 35.8109 40.6685 21.9148 121.1446 26.4629 -18.4976 33.8722 0.017 -165.2243 48.2201 40.6908 ... (8 Replies)
Discussion started by: malandisa
8 Replies

7. Shell Programming and Scripting

Match text and print/pipe only that text

I'm trying to pull an image source url from a html source file. I'm new with regex. I'm in BaSH. I've tried grep -E 'http.*jpg' file which highlights the text, but gives me 2 problems: 1) Results aren't stand alone and can't be piped to another command. (I believe it includes everything in... (5 Replies)
Discussion started by: amx401
5 Replies

8. Shell Programming and Scripting

Match text from file 1 to file 2 and return specific text

I hope this makes sense and is possible. I am trying to match $1 of panel_genes.txt with $3 of RefSeqGene.txt and when a match is found the value in $6 of RefSeqGene.txt Example: ACTA2 is $1 of panel_genes.txt ACTA2 NM_001613.2 ACTA2 NM_001141945.1 awk 'FNR==NR {... (4 Replies)
Discussion started by: cmccabe
4 Replies

9. Shell Programming and Scripting

Using awk to remove lines from file that match text

I am trying to remove each line in which $2 is FP or RFP. I believe the below will remove one instance but not both. Thank you :). file 12 123 FP 11 10 RFP awk awk -F'\t' ' $2 != "FP"' file desired output 12 11 (6 Replies)
Discussion started by: cmccabe
6 Replies

10. Shell Programming and Scripting

Match all lines in file where specific text pattern is less than

In the below file I am trying to grep or similar, all lines where only AF= is less than 0.4.. Thank you :). grep grep "AF=" ,+ .4 file file 12 112036782 . T C 34.0248 PASS ... (3 Replies)
Discussion started by: cmccabe
3 Replies

LEARN ABOUT MINIX

grep

GREP(1) 						      General Commands Manual							   GREP(1)

NAME

       grep - search a file for lines containing a given pattern

SYNOPSIS

       grep [-elnsv] pattern [file] ...

OPTIONS

       -e     -e pattern is the same as pattern

       -c     Print a count of lines matched

       -i     Ignore case

       -l     Print file names, no lines

       -n     Print line numbers

       -s     Status only, no printed output

       -v     Select lines that do not match

EXAMPLES

       grep mouse file	   # Find lines in file containing mouse

       grep [0-9] file	   # Print lines containing a digit

DESCRIPTION

       Grep  searches  one  or	more  files (by default, stdin) and selects out all the lines that match the pattern.  All the regular expressions
       accepted by ed and mined are allowed.  In addition, + can be used instead of * to mean 1 or more occurrences, ? can be used to mean 0 or  1
       occurrences,  and  |  can  be used between two regular expressions to mean either one of them.  Parentheses can be used for grouping.  If a
       match is found, exit status 0 is returned.  If no match is found, exit status 1 is returned.  If an error is detected,  exit  status  2	is
       returned.

SEE ALSO

       cgrep(1), fgrep(1), sed(1), awk(9).

																	   GREP(1)
All times are GMT -4. The time now is 01:47 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy