How to replace a column of a CSV file with lines from another file in BASH?

Question

I have a 4-column CSV file, data.csv using "@" as the separator, e.g.:

1@fish@ocean@likes to swim in the ocean
2@whale@ocean@likes to swim in the ocean

To edit just the 4th column, I used this command:

awk -F "@*" '{print $4}' data.csv > temp.csv

Then I ran some additional scripts to modify temp.csv.

Now, I need to return the contents of temp.csv to data.csv, replacing everything in the 4th column of data.csv.

How can I replace the contents of the 4th column of data.csv with the edited lines in temp.csv?

perreal · Accepted Answer · 2013-11-09 12:57:29Z

4

You can also use paste and cut:

cut -d@ -f1-3 data.csv | paste -d@ - temp.csv

answered Nov 9, 2013 at 12:57

perreal

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Comments

pobrelkey · Accepted Answer · 2013-11-09 13:09:40Z

3

I upvoted the other answer, but to give you an idea of the approach in awk:

Having first prepared your temp.csv file:

$ cut -d@ -f4 data.csv | sed -e 's,ocean,lava,g' > temp.csv

You then read a line from temp.csv as you read each line from data.csv, overwriting the fourth field in the line:

$ awk -F@ -vOFS=@ '{ getline $4 < "temp.csv" ; print }' data.csv
1@fish@ocean@likes to swim in the lava
2@whale@ocean@likes to swim in the lava

answered Nov 9, 2013 at 12:56

pobrelkey

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Or, even easier, sed 's/\(.*@\)\(.*\)ocean\(.*\)/\1\2lava\3/g' data.csv (no need for a temporary file).