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up vote 2 down vote favorite

I have several plain text tables (table.txt), with time series going from 2005 until 2099. Unfortunately some of them are missing the last day of the time series 31.12.2099, as follow:

YEAR MONTH DAY RES
2005 1     1   1000
2005 1     2   1001
[...]
2099 12    29  1002
2099 12    30  1003

How can I add the missing day of the time series (31.12.2099) by pasting the value (RES) of the previous day? Considering the minimal example provided, the output should look like that:

YEAR MONTH DAY RES
2005 1     1   1000
2005 1     2   1001
[...]
2099 12    29  1002
2099 12    30  1003
2099 12    31  1003
share|improve this question
    
This is a task with many sub-tasks. Which of these sub-tasks is causing you problems? – Stig Hemmer yesterday
    
Are you permitted to use awk or perl? – Mark Plotnick yesterday
    
@StigHemmer - The first problematic task is to find which table missed the 31.12.2099. Afterward I think I am able to paste the value of the previous day. – steve yesterday
    
@MarkPlotnick - Definitely permitted to use them! – steve yesterday
    
How are the columns delimited? A single tab? Multiple spaces? – Mark Plotnick yesterday

3 Answers 3

up vote 3 down vote accepted

With awk:

awk '{a=$0}1; END{$0=a; if($1==2099&&$2==12&&$3==30){$3=31;print}}' file | column -t
  • r=$0 set the a variable to the whole line.
  • 1 a true condition that all line are printed
  • END{...} that block is executed when all lines are processed
    • $1==2099&&$2==12&&$3==30 if the last line was december 30th, 2099 (the 13th is missing)
    • $3=31 set the day to 31
    • print and print that additional line.
  • column -t is to columnate the list.

The result with your input file:

YEAR  MONTH  DAY  RES
2005  1      1    1000
2005  1      2    1001
...
2099  12     29   1002
2099  12     30   1003
2099  12     31   1003
share|improve this answer
up vote 1 down vote

The script adds to all table files which have 30 in the last line followed by 2 space and 4 symbols RES the new line with 2099 12 31 RES(from line before): 

sed -i '$ s/30\(  ....\)$/&\n2099 12    31\1/' table*
share|improve this answer
up vote 1 down vote

Assuming your file names all start with table (if they don't, just change the glob pattern to something that matches all of them), you can do:

for file in table*; do
    awk -vi="2099 12    31" '1;END{if($0!=i){print i,$NF}}' "$file" > "$file".new
done

The awk command defines the variable i to be the missing line. The 1; just prints every line and the END{} block is executed once the entire file has been read. When inside the END{} block, $0 will be the last line read, the last line of the file. If that is not equal to the value of i, print i and the last field (NF) of the last line of the file.

share|improve this answer
    
@Costas d'oh! Of course, very good point. Thanks and fixed. – terdon♦ yesterday

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