Sort a text file

sort sampleIDs.txt > sampleIDs_sorted.txt

get unique list of  sorted text elements

sort -u sampleIDs.txt > sampleIDs_unique_sorted.txt

Word frequencies

Get for each element (word/string) in a list the frequency of it's occurrence (sorted)

# Count the number of repeats for each ID in the list

sort sampleIDs.txt | uniq -c | awk '{print $2"\t"$1}' | sort -rnk 2

Sorted list of files

Sorting list of files

ls *.txt | sort