Have this peculiar requirement to print files in a given directory in the below mentioned format

filename1 <type of file> owner group
filename2 <type of file> owner group

The separator between columns being a tab.

I have been able to write the following command but the output of system command introduces a new line which I wish to avoid

find . -type f | xargs -I{} ls -let {} | awk -F" " 'BEGIN{OFS="\t" ORS=":"} {cmd=sprintf("file \"%s\"", $10);system(cmd);print $3,$4}'| tr -s ':\t ' '\t'

The produces the output as follows
filename1 <type of file>
owner group filename2 <type of file>
owner group $

I understand that the system command is reposnsible for the new line which I wish to avoid - I used ORS for the same reason but no luck.
Any help would be much appreciated.


You can use piped I/O from a command in awk (at least gawk, I haven't tested this on Solaris):

find . -type f | xargs ls -l | awk 'BEGIN { OFS="\t" } { command=sprintf("file \"%s\"", $9); command | getline type; close(command); print type, $3, $4 }' | tr ":" "\t"

If your find supports it you can simplify this with

find . -type f -ls | awk ...

There's a handy resource on using getline which covers a number of caveats (including not using close() as I had initially).

  • Worked like a charm. Thanks for the great tip using readline. – Prasoon May 6 '15 at 8:57
  • Wanted to know, is there a way I can perform an if condition analysis on the output of the file command above? Say, if the file output says that the file is an ELF executable, can I run ldd and display the output alongside? – Prasoon May 11 '15 at 4:56
  • If you have another question you should really ask a new question. Nevertheless, you can use type in the same way as any other variable, in particular in an if condition after getline (... getline type; if (type ...) { ... }; print type, $3, $4). Try it and see... – Stephen Kitt May 11 '15 at 5:11
  • Realized that after running the original command you gave, without using close, I run into instances of "awk: line 0 (NR=252): too many open streams to getline onto "file "some filename here"" kind of issue. – Prasoon May 11 '15 at 8:06
  • Indeed, I'll update my answer. – Stephen Kitt May 11 '15 at 8:47

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