When the lines of a file or directory get too long, upgrade to ls list format?

Question

Is there a way I can do this? For example if a gets a long name like:

i-have-names-that-are-too-long-to-describe/
i-have-names-that-are-too-long-to-describe-2/
i-have-names-that-are-too-long-to-descri-3/

Can I "upgrade" over from ls to ls -l given that I have a name of a file or directory that is longer than than say, 20 characters?

Is there a way to set up a bash function in my .bashrc to do this? I'll call the resulting function lls().

@tripleee asked:

Do you want ls -l when the input file name is long? Why? It will make the output longer, not shorter. What if you receive a mix of long and short filenames?

I want it more so that reading the long filenames are systematized to a list (and easier for me to digest and read going down a fixed column); for a mix of long and short filenames, I would default to the list format.

Answer 1

There's no builtin option in ls that does what you want. You'd have to parse the output then restart if "long" filenames are found, or do something like:

$ ls ??????????* >& /dev/null && ls -l || ls

(Put as many ? as your length limit. You can set that up as an alias.)

Why don't you simply use ls -1? (That's a one, not a lowercase L.) It always lists files in a single column. (Or pipe ls to more or less, which also goes to single column display.) Or use find with -maxdepth 1.

Answer 2

if [ $(ls "$@" | ( max=0; while read l ; do len=${#l} ; [[ $max -lt $len ]] && max=$len; done; echo $max )) -gt 20 ]
then
    ls "$@"
else
    ls -l "$@"
fi

or, thanks to manatwork suggestion, this much simpler way which assumes GNU wc is available:

[[ $(ls "$@" | wc -L) -gt 20 ]] && ls "$@" || ls -l "$@"

Answer 3

This is my independent attempt of what I wanted:

lls(){
  opt="   "      
  for i in $(ls -l | tr -s " " | cut -d' ' -f9)  
  do   
    count=$(echo $i | wc -m)  
     if [ $count -gt 20 ] ; then    
       opt=" -l"; break;           
     fi    
  done  
  ls $opt
}

I placed this in my .bashrc. This does require the use of tr, cut, and wc though.