Finding a number of occurrences of a certain character in tcsh

Question

I am trying to find the number of certain types of files that have a '_' in the filename.

I'm a massive beginner so my syntax looks like this at the moment;

foreach txt ( 'ls *.txt')
set n=0
if(grep _ txt) then
@ n = n+1
endif
end

It doesn't work as my if statement isn't correct, but I'm not sure how to define saying if the txt file has a '_' within the filename then increment n by 1.

Answer 1

One way of doing it would be to use the shell's globbing capabilities rather than using grep.

set n=0
foreach txt (*_*.txt)
    @ n++
end

The syntax for the "if grep" thing if you needed that for other reasons would be:

if ( { grep -q _ $var } ) then
  ...
endif

(-q tells grep to be quiet and not print out anything.)

Answer 2

To get the number of filenames that have a certain character use:

set n=`ls *.txt | fgrep -c _`

This will print only the filenames that have the character found and then count the number of entries returned. In tcsh, you need to prefix assignments with set.

Answer 3

You can use the find command in combination with wc to get the number of file with a _ in the name:

set n=`find [path] -maxdepth 1 -name "*_*.txt" | wc -l`

Replace [path] with the directory you would like to search.