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Save output of updated csv file as csv file itself


 
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# 1  
Old 03-30-2015
Save output of updated csv file as csv file itself

Hi, all

I want to sort a csv file based on timestamp from oldest to newest and save the output as csv file itself. Here is an example of my csv file.

test.csv
Code:
SourceFile,DateTimeOriginal
/home/intannf/foto/IMG_0739.JPG,2015:02:17 11:32:21
/home/intannf/foto/IMG_0749.JPG,2015:02:17 11:37:28
/home/intannf/foto/IMG_0759.JPG,2015:02:17 11:49:09
/home/intannf/foto/IMG_0771.JPG,2015:02:17 11:51:22
/home/intannf/foto/IMG_0745.JPG,2015:02:17 11:36:01
/home/intannf/foto/IMG_0763.JPG,2015:02:17 11:49:45
/home/intannf/foto/IMG_0666 (1).JPG,2015:02:17 09:59:48
/home/intannf/foto/IMG_0782.JPG,2015:02:17 11:54:16
/home/intannf/foto/IMG_0750.JPG,2015:02:17 11:37:29
/home/intannf/foto/IMG_0762.JPG,2015:02:17 11:49:24
/home/intannf/foto/IMG_0752.JPG,2015:02:17 11:37:40
/home/intannf/foto/IMG_0684.JPG,2015:02:17 10:54:51
/home/intannf/foto/IMG_0687.JPG,2015:02:17 10:56:43
/home/intannf/foto/IMG_0777.JPG,2015:02:17 11:53:43
/home/intannf/foto/IMG_0756.JPG,2015:02:17 11:45:21
/home/intannf/foto/IMG_0746.JPG,2015:02:17 11:37:18
/home/intannf/foto/IMG_0743.JPG,2015:02:17 11:34:26

Output required
Code:
SourceFile,DateTimeOriginal
/home/intannf/foto/IMG_0666 (1).JPG,2015:02:17 09:59:48
/home/intannf/foto/IMG_0684.JPG,2015:02:17 10:54:51
/home/intannf/foto/IMG_0687.JPG,2015:02:17 10:56:43
/home/intannf/foto/IMG_0739.JPG,2015:02:17 11:32:21
/home/intannf/foto/IMG_0743.JPG,2015:02:17 11:34:26
/home/intannf/foto/IMG_0745.JPG,2015:02:17 11:36:01
/home/intannf/foto/IMG_0746.JPG,2015:02:17 11:37:18
/home/intannf/foto/IMG_0749.JPG,2015:02:17 11:37:28
/home/intannf/foto/IMG_0750.JPG,2015:02:17 11:37:29
/home/intannf/foto/IMG_0752.JPG,2015:02:17 11:37:40
/home/intannf/foto/IMG_0756.JPG,2015:02:17 11:45:21
/home/intannf/foto/IMG_0759.JPG,2015:02:17 11:49:09
/home/intannf/foto/IMG_0762.JPG,2015:02:17 11:49:24
/home/intannf/foto/IMG_0763.JPG,2015:02:17 11:49:45
/home/intannf/foto/IMG_0771.JPG,2015:02:17 11:51:22
/home/intannf/foto/IMG_0777.JPG,2015:02:17 11:53:43
/home/intannf/foto/IMG_0782.JPG,2015:02:17 11:54:16

and this is my script:
Code:
sort --field-separator=',' --key=2 -n test.csv > test.csv

Unfortunately, when i checked them out, there is no data in the test.csv. It is blank. Or it should be saved as another csv file? But i need to save it as csv file itself.

Please help me how to solve it. Thanks in advance.

Regards,
Intan
# 2  
Old 03-30-2015
If you read from a file and write to the same file in one operation, you'll end up corrupting the file. Work-around is to write to a temp file and then rename the temp file.
Code:
sort .... test.csv > temp
mv temp test.csv

This User Gave Thanks to balajesuri For This Post:
# 3  
Old 03-30-2015
The sort utility actually has an option to let you put the output in one of the input files... Try:
Code:
sort --field-separator=',' --key=2 -n -o test.csv test.csv

Note that since : is not a numeric character, using the -n option to sort means you are only sorting on the year in the 2nd field with your secondary sort key being the filename. If you want the month, day, hour, minute, and second portions of the 2nd field on these lines to participate in your primary sort key; remove the -n option.
This User Gave Thanks to Don Cragun For This Post:
# 4  
Old 03-30-2015
or:
Code:
awk -F, '{t=$2;gsub("[^0-9]","",t);print t, $0}' OFS=, test.csv | sort -n -k1,1 | cut -d, -f2-

This User Gave Thanks to vgersh99 For This Post:
# 5  
Old 03-30-2015
Quote:
Originally Posted by vgersh99
or:
Code:
awk -F, '{t=$2;gsub("[^0-9]","",t);print t, $0}' OFS=, test.csv | sort -n -k1,1 | cut -d, -f2-

This is extremely complicated for data that is in a form where a string comparison will work just fine (and, it doesn't solve the problem of redirecting the output wiping out the input). Just using standard sort utility options, the following does everything that was requested:
Code:
sort -k2,2 -o test.csv -t, test.csv

# 6  
Old 03-31-2015
Thanks for your helps, balajesuri, Don Cragun and vgersh99! Smilie

Now I can save my csv file as csv file itself. and personally, i like one line code because it looks simple and not complex. So, i prefer to use Don Cragun's code. I used this code:
Code:
sort --field-separator=',' --key=2 -n -o test.csv test.csv

Because when i tried to run this code:
Code:
sort -k2,2 -o test.csv -t, test.csv

the output that i got is like this:
Code:
/home/intannf/foto/IMG_0666 (1).JPG,2015:02:17 09:59:48
/home/intannf/foto/IMG_0684.JPG,2015:02:17 10:54:51
/home/intannf/foto/IMG_0687.JPG,2015:02:17 10:56:43
/home/intannf/foto/IMG_0739.JPG,2015:02:17 11:32:21
/home/intannf/foto/IMG_0743.JPG,2015:02:17 11:34:26
/home/intannf/foto/IMG_0745.JPG,2015:02:17 11:36:01
/home/intannf/foto/IMG_0746.JPG,2015:02:17 11:37:18
/home/intannf/foto/IMG_0749.JPG,2015:02:17 11:37:28
/home/intannf/foto/IMG_0750.JPG,2015:02:17 11:37:29
/home/intannf/foto/IMG_0752.JPG,2015:02:17 11:37:40
/home/intannf/foto/IMG_0756.JPG,2015:02:17 11:45:21
/home/intannf/foto/IMG_0759.JPG,2015:02:17 11:49:09
/home/intannf/foto/IMG_0762.JPG,2015:02:17 11:49:24
/home/intannf/foto/IMG_0763.JPG,2015:02:17 11:49:45
/home/intannf/foto/IMG_0771.JPG,2015:02:17 11:51:22
/home/intannf/foto/IMG_0777.JPG,2015:02:17 11:53:43
/home/intannf/foto/IMG_0782.JPG,2015:02:17 11:54:16
SourceFile,DateTimeOriginal

the header is written below the data. Would you tell me why it can be like that?
# 7  
Old 03-31-2015
Sorry, I didn't notice the heading line before. Doing a numeric sort, the string DateTimeOriginal evaluates to 0 and sorts before 2015; while doing an alphanumeric sort, numbers sort before letters. So, you need the -n option to make the heading come out first. If you use numeric sorting, you need to make the sort key more complex to use the each year, month, day, hour, minute, and second field separate keys to avoid just using the year as your sort key:
Code:
sort -n -k2.1,2.4 -k2.6,2.7 -k2.9,2.10 -k2.12,2.13 -k2.15,2.1 -k2.18,2.19 -o test.csv -t, test.csv

But with your data we can use numeric sorting for the year and use alphanumeric sorting for the month, day, hour, minute and second as a single field, which siimplifies the command to just:
Code:
sort -k2.1,2.4n -k2.6,2 -o test.csv -t, test.csv

Your relatively simple sort seems to work because the image numbers in your pathnames are monotonically increasing as the time stamp increases AND all of your image files are in a single directory. If your real image files could be in more than one directory, might have different numbers of digits in the sequence numbers, or might come from different cameras with different image ranges, one of the above sort commands should sort correctly by date and time for you.
This User Gave Thanks to Don Cragun For This Post:

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