Question

I have a file like:

something1

something2 201101130000

thing

thing1

thing2

AAA, -2, 4, 0, 54;

thing3

thing4

AAA, 43, 43, 0, 5, 0, 0,;

thing5

AAA, 132.0, 43.0,  0.0,  0.0, 43.0,210.0,'

thing5

How to copy the date (201101130000) from the second line, add a comma (,) then put the numbers of the line before last (132,0, 43.0, 0.0, 43.0, 210.0) in newfile.txt
the new file should look like:(the original file does not have spaces between lines as it is here)

20110113, 132.0, 43.0,  0.0,  0.0, 43.0,210.0

I tried grep and sed with no luck. Thanks for your help

Answer 1

Here’s how I’ve interpreted your question:

• You’re trying to ‘grep’ and join parts of two lines. These two lines are always the second and second last lines.

• You’re also trying to redirect output to another file. You can use shell redirection for this, like: awk ... file > outputfile.

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Here’s one way using sed:

sed '2h; $!N; $!D; ${ G; s/[^,]*\([^\n]*\).* \([0-9]\{8\}\).*/\2\1/; s/..$// }' file

Since you’ve tagged this as linux, I’m guessing you’ve got GNU sed and don’t mind golf:

sed -r '2h;$!N;$!D;${G;s/[^,]*([^\n]*).*\s([0-9]{8}).*/\2\1/;s/..$//}' file

Results:

20110113, 132.0, 43.0,  0.0,  0.0, 43.0,210.0

Explanation:

2h         # copy the second line to hold space
$!N        # if not the last line append the next line
$!D        # if not the last line delete up to the first newline in the pattern
$ { ... }  # one the last line, perform two substitutions   

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Alternatively, awk may be easier to understand:

awk 'FNR==NR { c++; next } FNR==2 { x = substr($NF,0,8) } FNR==c-1 { sub(/[^,]*/,x); sub(/..$/,""); print }' file file

Results:

20110113, 132.0, 43.0,  0.0,  0.0, 43.0,210.0

Explanation:

FNR==NR { c++; next }    # read the first file in the arguments list, to get a 
                         # count of the number of lines in the file
FNR==2 { ... }           # when reading the second line of the second file in the
                         # arguments list, take a substring of the last field
FNR==c-1 { ... }         # one the second last line of the second file in the
                         # arguments list, perform two substitutions and print
                         # the line.