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I have a text file, each line is stored like this :

"Video or movie"    "parent"    "Media or entertainment"    "1" "1" "1" "0" "0"

I want to swap the columns 3 with 2, i.e.

"Video or movie"   "Media or entertainment"  "parent"   "1" "1" "1" "0" "0"

How to do it in linux in a shell script or any other scripting language? I just need a simplest and quickest way of doing it.

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Your last sentence is incomplete. –  Faheem Mitha Feb 14 '12 at 3:18
    
You could give R a try. –  Faheem Mitha Feb 14 '12 at 3:41
    
A CSV processor, with whitespace as the column separator? –  Gilles Feb 14 '12 at 7:41
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6 Answers

up vote 4 down vote accepted

It can be done with awk using " as the field separator. But doing that, you must remember that $1 is empty, $2 holds the first string, $3 is the space between strings, $4 is the second string, etc. Also, it's more reliable to swap the two strings instead of just printing all the fields and hoping you put enough $ns. Bearing these in mind, the following should work:

awk 'BEGIN{OFS=FS="\""} {tmp=$4;$4=$6;$6=tmp;print}' input_file >output_file
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+1 for such an elegant use of awk. –  Stephen Quan Feb 14 '12 at 3:23
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Here goes a quick and dirty sed that does it:

sed -e 's/^\("[^"]*"\) *\("[^"]*"\) *\("[^"]*"\)/\1 \3 \2/'

But will fail for fields with double quotes in their values, etc.

An example:

echo \"a\" \"b\" \"c d d d\" \"e\" | sed -e 's/^\("[^"]*"\) *\("[^"]*"\)  *\("[^"]*"\)/\1 \3 \2/'

But I'm pretty sure someone will be able to show you an awk one-liner that is simpler and better.

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it did not work for this line: "bored of the main" "melody" "main plot" "1" "1" "1" "0" "1.0" "0" "0" –  frankmoss Feb 13 '12 at 20:49
    
@frankmoss I get '"bored of the main" "main plot" "melody" "1"', is that not what you want? What are you getting? –  Kevin Feb 13 '12 at 21:02
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It might be a white-space issue, try changing ` *` to [ \t]*. –  Kevin Feb 13 '12 at 21:03
    
@Kevin i get the original line. I replaced with [ \t]* but no change in the result. How does your sed look? –  frankmoss Feb 13 '12 at 21:16
    
@frankmoss I put in echo '"bored of the main" "melody" "main plot" "1"' | sed -e 's/^\("[^"]*"\) *\("[^"]*"\) *\("[^"]*"\)/\1 \3 \2/', and got out "bored of the main" "main plot" "melody" "1" - copied and pasted, no typos in either. GNU sed version 4.2.1 –  Kevin Feb 13 '12 at 21:23
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I'd go with:

sed 's/"\(.*\)"/\1/' |
    awk 'BEGIN{FS="\" +\"";OFS="\" \""}{t=$3;$3=$2;$2=t;print}' |
    sed 's/.*/"&"/'

The two sed scripts handle the leading and trailing double quotes (since they are not delimitors and interfere). The BEGIN clause handles the separation of fields. The t=$3;$3=$2;$2=t is a standard swap fields idiom, then the whole field is printed (with OFS as the field separator).

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it does not work. I send a single line file, and it prints the same file. –  frankmoss Feb 13 '12 at 21:49
    
Using your input ("Video or movie" "parent" "Media or entertainment" "1" "1" "1" "0" "0") and copying the above (not using my previous incarnations), I get "Video or movie" "Media or entertainment" "parent" "1" "1" "1" "0" "0". –  Arcege Feb 13 '12 at 22:26
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This method is effectively identical to Kevin's awk method.. I've include it here just as a comparison between bash and awk.

IFS=\";   # IFS sets up the split-at array delimiter
cat file |
while IFS= read -r line ;do              # Disable IFS for each `read' 
    A=($line)                            # split into array elements
    t="${A[5]}";A[5]="${A[3]}";A[3]="$t" # swap "columns" 2 and 3
    for ((i=1;i<$((${#A[@]}));i++)) ;do
       printf '"%s' "${A[$i]}"           # print each element with a lead "
    done; echo '"'                       # add the final "
done
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What about something like this:

awk '{print $1, $3, $2, $4, $5, $6, $7, $8}' file > newfile
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@ramonovsky awk doesn't like combination of quotes and space... i.e. it does not work –  frankmoss Feb 13 '12 at 21:25
    
You can specify ' ' as -F (field separator) –  ramonovski Feb 13 '12 at 21:28
    
And what does -F' ' do? The problem is that this will print (e.g. in the first case) "Video movie" or "parent" ...`, quite clearly not what frank wants. –  Kevin Feb 13 '12 at 22:32
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I have two solutions.

ANSWER ONE: Use sed 3 times to do the following:

  1. start with the original line: 12345678
  2. duplicate the first two parameters: 1212345678
  3. chop the 4th parameter: 121345678
  4. chop the 1st parameter: 21345678

Here's the resultant command using sed (Using XXX and YYY as helpers to find and remove the 1st and 4th parameters):

sed 's/["][^"]*["][^"]*["][^"]*["]/XXX& & YYY/' data.txt | sed 's/["][^"]*["] YYY//' | sed 's/XXX["][^"]*["]//'

ANSWER TWO: Convert data into a script and run it!

  • convert the data.txt into a data.sh by inserting a command (say flipcol.sh)
  • run the data.sh

Implement flipcol.sh as:

echo '"'$2'"' '"'$1'"' '"'$3'"' '"'$4'"' '"'$5'"' '"'$6'"' '"'$7'"' '"'$8'"'

Then run the following command on your data.txt creating a shell script:

sed 's!^!./flipcol.sh !' < data.txt > data.sh

Then run the newly created shell script

./data.sh
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