zadanie 1.
mkdir -p level1/level2_2/level3

zadanie 3.
more -N littleprince.txt

zadanie 5.
wget ...
gunzip pssb_sample.bed.gz
sed s/"chr7"/"7"/g pssb_sample.bed
grep "+" pssb_sample.bed | wc -l > output.txt
grep "-" pssb_sample.bed | wc -l >> output.txt
sort -nr output.txt

zadanie 6.
sort -k2,2 -nr pssb_sample.bed | uniq | grep -c "+"