LinuxQuestions.org - [SOLVED] tab seperated textfile and write each field in a variable

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Midyr

04-23-2021 04:28 AM

tab seperated textfile and write each field in a variable

Hello,

I have a textfile with tab separate content.

The goal is, to insert fiels3 in some lines.

The first line is without field3.

filed6 contains a space, which makes the trouble

Code:

F1      F2              F4      F5      F 6

F1      F2      F3      F4      F5      F 6

My idea was, to do this with awk, and write each field in a variable but it dosen't work as expected.

Code:

#!/bin/bash



while read 

do 



xy=($(awk -F '\t' '{print $1, $2, $3, $4, $5, $6}' )) 

echo "Status; "${xy[0]}

echo "Start: "${xy[1]}

echo "End: "${xy[2]}

echo "Snr:: "${xy[3]}

echo "Ubknn: "${xy[4]}

echo "CN: "${xy[5]}

done < index.txt

Code:



Status; F1

Start: F2

End: F3

Snr:: F4

Ubknn: F5

CN: F

As you can see, F6 is cuted after the space.

Any idea to this?

Thanks

Midyr

pan64

04-23-2021 04:39 AM

you do not need to use awk at all:
https://github.com/koalaman/shellcheck/wiki/SC2206

Code:

xy=($(awk -F '\t' '{print $1, $2, $3, $4, $5, $6}' ))

awk will use tab, but shell will split the line second time using whitespace.
did you check xy[6] ?

Turbocapitalist

04-23-2021 04:50 AM

But if you do use AWK, keep in mind that the Field Separator (FS) and the Output Field Separator (OFS) are different variables.

Code:

xy=($(awk 'BEGIN {FS="\t"; OFS="\t"} {print $1, $2, $3, $4, $5, $6}' ))

Midyr

04-23-2021 04:54 AM

Quote:

Originally Posted by pan64 (Post 6244082)

you do not need to use awk at all:
https://github.com/koalaman/shellcheck/wiki/SC2206

Code:

xy=($(awk -F '\t' '{print $1, $2, $3, $4, $5, $6}' ))

awk will use tab, but shell will split the line second time using whitespace.
did you check xy[6] ?

Yes, xy[6] has the second part, I also tried some escapes, without success

grail

04-24-2021 03:56 AM

As the formatting wasn't saved for me on pasting, may I ask what is at field 3 in the line where it is missing?

I have assumed 2 spaces to make up for the missing field, so the below shows how bash can handle this:

Code:

!/usr/bin/env bash



while IFS=$'\t' read -ra fields

do

        printf "##%s##\n" "${fields[@]}"

done<your_file

And the output shows what it would pick up:

Code:

$ ./script.sh 

##F1##

##F2##

##  ##

##F4##

##F5##

##F 6##

##F1##

##F2##

##F3##

##F4##

##F5##

##F 6##

pan64

04-24-2021 04:00 AM

Quote:

Originally Posted by Midyr (Post 6244087)

Yes, xy[6] has the second part, I also tried some escapes, without success

did you check the link I posted? You will see the solution (and explanation too).

shruggy

04-24-2021 04:13 AM

Quote:

Originally Posted by Midyr (Post 6244078)

The goal is, to insert field3 in some lines.

Then I don't understand what is the purpose of writing out each field to a variable.

Code:

awk -F\\t -vOFS=\\t '1,$3!=""&&$3="NEW"' index.txt

Midyr

05-03-2021 01:18 AM

Quote:

Originally Posted by shruggy (Post 6244399)

Then I don't understand what is the purpose of writing out each field to a variable.

Code:

awk -F\\t -vOFS=\\t '1,$3!=""&&$3="NEW"' index.txt

Thanks, that's, what i'm locking for!

MadeInGermany

05-04-2021 08:40 PM

Does it print all lines?
The following has an unconditional and explicit print

Code:

awk 'BEGIN { FS=OFS="\t" } $3=="" { $3="NEW" } { print }' < index.txt

The condition is $3==""

With bash builtins:
have a while read loop over the lines.
There is no good function to print with embedded delimiters,
so here is one.

Code:

#!/bin/bash

fs=$'\t'



prtjoin(){

  local fs=$1

  printf "%s" "$2"

  if [[ $# -gt 2 ]]

  then

    shift 2

    printf "$fs%s\n" "$@"

  fi

  printf "\n"

}



while IFS=$fs read -ra fields

do

  [[ -z ${fields[2]} ]] && fields[2]="NEW"

  prtjoin "$fs" "${fields[@]}"

done < index.txt

The condition is [[ -z ${fields[2]} ]]

And another variant:

Code:

#!/bin/bash

fs=$'\t'

while IFS=$fs read -ra fields

do

  [[ -z ${fields[2]} ]] && fields[2]="NEW"

  out=$(printf "$fs%s" "${fields[@]}"); printf "%s\n" "${out#$fs}"

done < index.txt

shruggy

05-05-2021 04:10 AM

@MadeInGermany. Two problems with your Bash code:

1) read counts consecutive runs of an IFS character as one delimiter. Probably not was the OP wanted.
2) \n in printf "$fs%s\n" "$@" is unnecessary.

And a small enhancement:

Code:

out=$(printf "$fs%s" "${fields[@]}")

is the same as

Code:

printf -v out "$fs%s" "${fields[@]}"

pan64

05-05-2021 04:30 AM

or probably

Code:

printf -v out "$fs%s" "${fields[*]}"

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