# List the unbroken sysmlinks under a directory.
$ ls -ld /my/path/**/*(D@-^@)
# rename file contents with its directory name as a prefix
$ zmv '(*)/(*.txt)' '${1}_$2'
# sorting file's names in ascending order according to the last two numerical fields of the files
# names. And then cat these files into one based on the ascending order depicted here.
$ find . -type f -regex ".*[.][0-9]+[.][0-9]+$" -print0 |sort -Vz | xargs -r0 cat > myfile
# or - with zsh -
$ cat ./*.<->.<->(n)
# Eliminate the duplicated elements of an array and keep the remain emements order appeared in the original array.
$ a=( a a f 1 3 b b 3 5 4 4 )
$ a=("${(u@)a")