UNIX for Dummies Questions & Answers

Hi Folks,

I have a requirement to develop a shell script. PFB my requirement,

Requirement:
I need to check an empty line after the end of each header in respective file and if a empty line is present simply echo file OK and if empty line is not present echo "Adding empty line" and add an empty line to an existing file with out modifying any other content in the same file.

My Problem:
The problem where I am stuck is there are four files and in each file the header is spanned into multiple lines with no specific format (In other words dynamic, In one file the header is spanned in 4 lines , in other 5 lines and in other 6 lines). I am not able to find a way how to check the end of header and accomplish my above requirement.

I have googled and read many articles but could not find a relevant answer. It would be of great help if you can help me out.

I have attached the sample files (In fact the original files which I am testing) for your reference. Please help me out.

With Regards,
TPK

In fact, there's not a single file in your samples that has an empty line after the header. MClubAnn_20150204.txt seems to have but has a <CR> (0x0D, carriage return) char in it. All the other have numerous (empty) fields in them.
It will be very difficult to tell header from data, nothing I'd dream up would work consistenly:
- not the field count
- not the structure (string fields vs. numeric fields)
- not unpaired double quotes

Plus, some seem to have header above the headers?

Hi,
maybe to search first line with field in format [0-9][0-9]/[0-9][0-9]/[0-9][0-9], and all line before this line are "The Header" ?

Regards.

Hi Rudic and disedorgue,

Thank You for your thoughts. Even I thought of similar options but nothing worked.

If we forget about the header, presuming that the header will not be more than 5 rows, how to add an empty line after 5th line in every file if there is no empty line.

Some times the requirements seem to be crazy which will make us mad spending hours

With Regards,
TPK

with gnu sed (not tested):

Code:

sed -e '5s/^..*$/\n&/' file

Regards.

Hi disedorgue,

I have tried with that it's not working, I have tried with the MClubWA_20150204.txt file.

I have executed the below command and taken count, the count seems to be same as 26 before executing the command and after executing the command.

Code:

sed -e '5s/^..*$/\n&/' MClubWA_20150204.txt|wc -l

And I want to append it to existing file only but sed seems to print the result on console. Please let me know it would be of great help for me. I am trying this for past 4 days.

With Regards,
TPK

Yes, sed writes the results it produces to its standard output. If you want the output saved in a file, you can redirect its output.

What operating system and shell are you using?

All of your sample files have some lines containing <carriage-return> characters. Some (maybe all) of your sample files have some lines that do not contain <carriage-return> characters. If these lines did not contain <carriage-return> characters, the standards would call these blank lines. Are you trying to create output files in DOS format (with all lines terminated by <carriage-return><newline> or are you trying to create output files in UNIX format (no <carriage-return>, just <newline> as the line terminator)?

What is your definition for empty line? The standards define an empty line to be a line that only contains one character (the <newline> character that terminates that line). Some of your files contain lines that only contain lots of <tab> characters terminated by a <carriage-return><newline> character pair. Do you consider that to be an empty line? Some of the DOS format blank lines appear as line 2 or 3 and are followed by other lines that still appear to be part of your headings. Some of your DOS format blank lines appear after what seems to be that file's heading and before that file's data.

Do you want add an empty line to your output file between the 5th and 6th input lines from your input files and also suppress copying all blank lines from your input (after removing <carriage-return>s)?