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up vote 1 down vote favorite

I am trying to perform the following : 

printf "Are you sure you want to copy %s (y/n) ? (file bigger than 10 MB) " "$0"

It works fine, nevertheless, I would like to display the actual size of my file, by doing something like : 

printf "Are you sure you want to copy %s (y/n) ? (file bigger than 10 MB : %s) " "$0" "ls -l $0 | awk {'print $5'}"

However, I have a failure by doing so. I guess it is not the right way to do it.

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3 Answers 3

up vote 2 down vote 
printf "Are you sure you want to copy %s (y/n) ? (file bigger than 10 MB: %lu) " "$0" \
  "$(wc -c < "$0")"

parsing the output of ls is not reliable (and you've forgotten the $(...) around it).

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up vote 0 down vote

I assume this is in some form of shell like bash or ksh. X is the file (I also supposed it has space in its name)

printf "Are you sure you want to copy %s (y/n) ? (file bigger than 10 MB : %s) " "$x" \
   $(ls -ld -- "$x" | awk {'print $5'})

should do.

Please note the $( some code ) syntax.

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up vote 0 down vote

If on a GNU system, prefer to use stat instead:

printf "Are you sure you want to copy %s (y/n) ? (file bigger than 10 MB : %s) " "$0" \
    "$(exec stat -Lc '%s' -- "$0")"
  • -L makes stat follow symlinks.
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Note that ksh (as in the question's title) often suggests non-GNU systems. There are a number of different stat commands. The stat -c %s syntax is specific to GNU stat –  Stéphane Chazelas Aug 6 '14 at 13:54
    
@StéphaneChazelas Nicely done edit. Looks like people in unix.stackexchange.com is also strict with -- :) –  konsolebox Aug 6 '14 at 13:55
    
Yes, though unfortunately -- will not always be enough here. For instance it still won't work for a file called -. Which is why I'd recommend to use the portable wc -c < "$0" which has none of those issues (that gives a different result for symlinks though and would fail if you don't have read permission to the file). See also stat -c %s - < "$0" –  Stéphane Chazelas Aug 6 '14 at 13:58
    
Portability is always something that could cause debate so I'd avoid that. But just to tell, I prefer easier or more practical solutions when they're available on a target tool or system. If something's better I'd use it or propose it even if it's less portable as long as it suffice the requirements. In this instance, I see that stat could be better as it may no longer require to read the whole file just to get its size. –  konsolebox Aug 6 '14 at 14:04
    
wc doesn't read the whole size either if the file is a regular file (in all except old obscure implementations like old busybox ones) –  Stéphane Chazelas Aug 6 '14 at 14:16

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