Linux
# split a file to several files with n lines
split -l n file
sed
#replace something in the file
paste
cat
#two commands to combine file together
# check the column number in a file
cat file.txt | awk '{print NF}' | sort -n | uniq
# split a file to several files with n lines
split -l n file
sed
#replace something in the file
paste
cat
#two commands to combine file together
# check the column number in a file
cat file.txt | awk '{print NF}' | sort -n | uniq