1) Reordering one csv file based on another file header and 2) Merging one column of one csv file to another and remove duplicate

Question

I have two csv file. Both files might have same or different data. File2 has only few columns from file 1. Some column in file 2 may have different header. eg File 2 has Name in place of First Name

Username, Identifier,One-time password,Recovery code,First name,Last name,Department,Location
booker12,9012,12se74,rb9012,Rachel,Booker,Sales,Manchester
grey07,2070,04ap67,lg2070,Laura,Grey,Depot,London
johnson81,4081,30no86,cj4081,Craig,Johnson,Depot,London
jenkins46,9346,14ju73,mj9346,Mary,Jenkins,Engineering,Manchester
smith79,5079,09ja61,js5079,Jamie,Smith,Engineering,Manchester

File 2

Department,First name,Last name,One-time password
Sales,Rachel,Booker,12se74
Depot,Laura,Grey,04ap67
Depot,Craig,Johnson,30no86
Engineering,Mary,Jenkins,14ju73
Engineering,Jamie,Smith,09ja61

Problem 1: I wanted to reorder columns in csv file 2 to match order in csv file 1 based on headers.

Desired output header sorted based on file 1

One-time password,Name,Last name,Department
12se74,Dash,Bok,Sales
04ap67,Claire,Trans,Accounts
30no86,Shane,Walter,Depot
14ju73,Leon,Jenkins,Engineering
09ja61,Oliver,Den,Engineering

Problem 2: Merge File2 columns to File 1 based on header removing duplicates Eg if First Name , Last Name, Department columns are same then those are duplicates remove those dupes. Other columns may or may not be same. Hence wanting to achive condition based deduplication of record

Problem 3: Convert file 2 as file 1 template add missing columns in order. Finally compare and delete duplicate columns based on certain headers. eg. If First Name, Last Name and password are same then they are duplicates other columns may be same or different.

Problem 4: Copy specific column from file 2 to file 1 preserving order Eg. File 2 has Name column Replace that column with First Name column of file 1

Tried:

awk -v FS=, -v OFS=, 'FNR==NR{hash[FNR]=$5; next}{$2 = hash[FNR]}1' file file2

Above answer is from https://unix.stackexchange.com/questions/674038/replace-a-column-value-in-csv-file-from-another-file

Above seem to work. But it requires to specify column numbet as $5 and $2. Can anyone help modify above command to specify header instead of column number

Tried

awk -v FS=, -v OFS=, '{ for (i=1;i<=NF;i++) { if (i=="name") var=$i }; FNR==NR{hash[FNR]=$5; next}{$var = hash[FNR] }' file file2

Not working

Answer 1

You can do it all quite easily with Miller, which is available here as a static binary. Put the mlr executable somewhere in your PATH and you're done with the installation.

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For starters, I'll assume that we're working with two CSV files with no inconsistency in the column names:

cat file1.csv

Username, Identifier,One-time password,Recovery code,First name,Last name,Department,Location
booker12,9012,12se74,rb9012,Rachel,Booker,Sales,Manchester

cat file2.csv

Department,First name,Last name,One-time password
Engineering,Oliver,Den,09ja61
Sales,Rachel,Booker,12se74

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rename a specified field:

mlr --csv rename 'First name,Name' file2.csv

Department,Name,Last name,One-time password
Engineering,Oliver,Den,09ja61
Sales,Rachel,Booker,12se74

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re-order the columns of file2.csv based on the header of file1.csv:

mlr --csv reorder -f "$(head -n 1 file1.csv)" file2.csv

One-time password,First name,Last name,Department
09ja61,Oliver,Den,Engineering
12se74,Rachel,Booker,Sales

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add missing columns in file2.csv based on the header of file1.csv:

mlr --csv template -t file1.csv file2.csv

Username, Identifier,One-time password,Recovery code,First name,Last name,Department,Location
,,09ja61,,Oliver,Den,Engineering,
,,12se74,,Rachel,Booker,Sales,

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remove duplicates based on One-time password,First name,Last name unicity:

mlr --csv head -n 1 -g 'One-time password,First name,Last name' fileX.csv

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concatenate file1.csv and file2.csv:

mlr --csv unsparsify file1.csv file2.csv

Username, Identifier,One-time password,Recovery code,First name,Last name,Department,Location
booker12,9012,12se74,rb9012,Rachel,Booker,Sales,Manchester
,,09ja61,,Oliver,Den,Engineering,
,,12se74,,Rachel,Booker,Sales,

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concatenate file1.csv and file2.csv and remove the duplicates based on One-time password,First name,Last name unicity:

The command is composed of a chain of operations.

mlr --csv unsparsify then head -n 1 -g 'One-time password,First name,Last name' file1.csv file2.csv

Username, Identifier,One-time password,Recovery code,First name,Last name,Department,Location
booker12,9012,12se74,rb9012,Rachel,Booker,Sales,Manchester
,,09ja61,,Oliver,Den,Engineering,

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Lastly, let's suppose that the column First name is called Name in file2.csv and that you want to concatenate file1.csv and file2.csv and remove the duplicates based on One-time password,First name,Last name unicity.

You can do it by prepending a rename operation to the previous command:

mlr --csv rename 'Name,First name' then unsparsify then head -n 1 -g 'One-time password,First name,Last name' file1.csv file2.csv