• echo(1)
• head(1)
• tail(1)
• cat(1)
• cut(1)
• paste(1)
• split(1)
• tr(1)
• printf(1)
• lam(1)
• join(1)
• sort(1)
• uniq(1)
• grep(1)
• sed(1)
• awk(1)

grep -r "some magic string" .

grep -v -e '^#' -e '^$' input.txt

diff --ignore-matching-lines='^\s*#' script1.sh script2.sh

cat << THISISEOF | cut -w -f2
a1  a2 a3
b1  b2 b3
c1  c2 c3
THISISEOF
## output contains three lines with "a2", "b2" and "c2"

paste -d";" in0.txt in1.txt in2.txt in3.txt > out.csv

cat << THISISEOF | awk '{s+=$2} END {print s}'
62 83 18
43 86 93
32 75 43
THISISEOF
## result is 244 (83+86+75)

cat << THISISEOF | awk '!NF{$0="XYZ"}1'
some
 
other
THISISEOF
## result contains "XYZ" in the second line

awk '!a[$0]++' input_file.txt

awk -v min=10 -v max=100 'BEGIN{srand(); print int(min+rand()*(max-min+1))}'

echo 54657374696e672031203220330 | xxd -r -p