Shell Programming and Scripting

Here's a streamlined awk version:

Code:

awk '/^E/ {next}
NF > 0'

The default action in awk is print, so a pattern with no action just prints the line. The first pattern/action pair skips lines that start with "E". Since awk does an autosplit into $1, $2, ... on each input line after trimming leading and trailing whitespace (with the default delimiter /[ \t]+/), if there are only spaces, there are no fields, i.e., NF == 0 is true.

Note that after closing an action, the awk parser is in a "pattern state", so the above could be written on one line:

Code:

awk '/^E/ { next } NF > 0'

or

Code:

awk 'NF > 0 || !/^E/'

Notice in the latter that the easier condition is checked first, i.e., the regexp pattern match is only done if there are non-space characters on the line. With a huge file (or repeated execution) this means the latter should perform better (this claim is not tested).

Thank you all for your help. Does anyone can recommand some books for shell scripting?

Thanks

This forum is a great start. Use the search function of this site as well - you'll find this question has been asked many times..

Now I have two flat text files, I only need to choose some of the fields from both files and combine into one file, then load to a database table. Is there any way to do it?

Thanks for your help.

You'll need to be a bit more descriptive with what you're trying to do here.. i.e. what lines inparticular are you going to want to pull out? Read up on the grep command. If you're looking for lines with the word "hi" in them, you'd use something like grep "hi" file1 file2 > new_file.