Shell Programming and Scripting

I think it is important to note that Scrutinizer's solution is the most efficient as it will need to read one line from each file. Any solution that uses something like

Code:

FNR == 1 { action }

will read all lines from all files. If the files being tested are large, this could take a significant amount of time to do an awful lot of unneeded I/O.

The only suggestion I'd make is to close the file after getting the first line. If there are a lot of files in the parameter list, not closing the file after use could result in exceeding the max open file descriptors limit for the process.

Code:

awk -F\| 'BEGIN{for(i=1;i<ARGC;i++){f=ARGV[i];print f,(getline<f)?NF:0; close(f);}}' *.txt

Thanks Scrutinizer. This was a very very helpful awk command (or rather a combination of commands).

---------- Post updated at 06:24 PM ---------- Previous update was at 06:22 PM ----------

Thanks Agama for the helpful addition.