$ curl cheat.sh/
# paste
# Merge lines of files.

# Join all the lines into a single line, using TAB as delimiter:
paste -s file

# Join all the lines into a single line, using the specified delimiter:
paste -s -d delimiter file

# Merge two files side by side, each in its column, using TAB as delimiter:
paste file1 file2

# Merge two files side by side, each in its column, using the specified delimiter:
paste -d delimiter file1 file2

# Merge two files, with lines added alternatively:
paste -d '\n' file1 file2

$
Follow @igor_chubin cheat.sh tldr