使用bash脚本重命名csv标头

Question

I want to rename the header of a csv file using bash script. Original csv file header looks like below:

temp.csv
    ,id,too,Issue,Valid,DPT,RH,TMP,U,V
    1,1,22383,2015-01-15 00:00:00 GMT,2015-01-15 00:00:00 GMT,269.8000183,80.90000153,272.6300049,3.039999962,-0.560000002
    1

            id  to  Issue   Valid   DPT RH  TMP U   V
      1     2    3  4        5      6   7    8  9   10

I 

want to rename column header as below:

 Cell   id  too Issue   Valid   DPT RH  TMP U   V
    1   2    3  4        5      6   7   8  9   10

Answer 1

You can use sed replace the header or the first line:

new_header=" Cell   id  too Issue   Valid   DPT RH  TMP U   V"
sed -i '' "1s/.*/$new_header/" file

This assumes that you don't have the sed expression separator / in your new header. In case you do, use a different separator in the sed expression.

Answer 2

You need to replace the first line with a different line. sed can do it for you:

sed -i -e "1 { r"<(echo ' Cell   id  too Issue   Valid   DPT RH  TMP U   V')"
d
}" file

To expand on the command

• -i edits the file in place (you can skip this)
• -e following is a sed command
• 1 execute the commands in the {} when you see the first line of input
• r inserts the text from the following "file"
• <( echo ' ... ') produces the new header on standard output, and assigns it to a file that is then readable by the sed command ( r will insert that text)
• d deletes the line

So, insert a new line of text and delete the old one.

If you do not need to edit the file in place, easier to do:

(
  echo ' Cell   id  too Issue   Valid   DPT RH  TMP U   V'
  tail -n +2 file
) > file.new