How to append several lines of text in a file using a shell script

Question

I want to write several lines (5 or more) to a file I'm going to create in script. I can do this by echo >> filename . But I would like to know what the best way to do this?

Answer 1

You can use a here document:

cat <<EOF >> outputfile
some lines
of text
EOF

Answer 2

I usually use the so-called "here-document" Dennis suggested. An alternative is:

(echo first line; echo second line) >> outputfile

This should have comparable performance in bash, as (....) starts a subshell, but echo is 'inlined' - bash does not run /bin/echo, but does the echo by itself.

It might even be faster because it involves no exec().

This style is even more useful if you want to use output from another command somewhere in the text.