Shell Programming and Scripting

# printf "%s" "ghw//yw/hw///??u" | sed 's@[^/]@@g' | wc -c
6

A='ghw//yw/hw///??u'
echo ${A//[^\/]} | wc -L
# ${VAR//<string>} means remove every occurence of <string> in VAR
# the regex [^\/] means anything but not slash (it must be escaped by \)

s="ghw//yw/hw///??u"
s=${s//[^\/]/}
echo ${#s}

$
$
$ echo "ghw//yw/hw///??u" | perl -lne 'print s|/||g'
6
$
$

awk '{print gsub("/",x)}' file

#  echo ghw//yw/hw///??u | sed -e 's/\///' -e's#[^/]##g' -e 's/./x\
/g' | sed -n '$='
6

$ echo ghw//yw/hw///??u | sed 's/\///; y/\//\n/' | sed -n \$=
6