UNIX for Dummies Questions & Answers

Hi All,

I have to append 2 lines at the end of a text file. If those 2 lines are already there then do not append else append the 2 lines to the text file.

Eg: I have a text file, file.txt

This text file might look like this,

/home/kp/make.jsp
/home/pk/model.jsp

I have to append these 2 lines /home/kk/file1.txt and /home/kk1/file2.txt at the end of file.txt.

Appended file looks like this,

file.txt:

/home/kp/make.jsp
/home/pk/model.jsp
home/kk/file1.txt
/home/kk1/file2.txt

The script has to check if file.txt has those lines /home/kk/file1.txt and /home/kk1/file2.txt before appending them at the end of the text file file.txt.

if the 2 lines already there in file.txt then the script should not append the 2 lines.

can someone please tell me how can I do this using korn shell.

Thanks
pavan

One can use tail and head to get the last two lines from a file:

Code:

 
one_before_last=$( tail -2 my_input|head -1 )
the_last_line=$(tail -1 my_input)

To determine if the line is present one can use grep -q - it will return 1 if not found, which can be used with

Code:

||

construct

To put it together one can do something like this:

Code:

 
#!/bin/ksh
input_file_1="your-name-here"
input_file_2="yeor-name-here"
my_output_file="your-name-here"
F1N1=$(tail -2 $input_file_1|head -1)
F1N2=$(tail -1 $input_file_1)
F2N1=$(tail -2 $input_file_2|head -1)
F2N2=$(tail -1 $input_file_2)
grep -q "$F1N1" $my_output_file || echo "$F1N1" >> $my_output_file
grep -q "$F1N2" $my_output_file || echo "$F1N2" >> $my_output_file
grep -q "$F2N1" $my_output_file || echo "$F2N1" >> $my_output_file
grep -q "$F2N2" $my_output_file || echo "$F2N2" >> $my_output_file

Hope this will give you an idea.