Indenting here documents

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You can indent the text inside here documents with tabs, you need to use the <<- redirection operator instead of <<:

$ cat <<- EOF
    This is some content indented with tabs `\t`.
    You cannot indent with spaces you __have__ to use tabs.
    Bash will remove empty space before these lines.
    __Note__: Be sure to replace spaces with tabs when copying this example.
EOF

This is some content indented with tabs _\t_.
You cannot indent with spaces you __have__ to use tabs.
Bash will remove empty space before these lines.
__Note__: Be sure to replace spaces with tabs when copying this example.

One practical use case of this (as mentioned in man bash) is in shell scripts, for example:

if cond; then
    cat <<- EOF
    hello
    there
    EOF
fi

It is customary to indent the lines within code blocks as in this if statement, for better readability. Without the <<- operator syntax, we would be forced to write the above code like this:

if cond; then
    cat << EOF
hello
there
EOF
fi

That’s very unpleasant to read, and it gets much worse in a more complex realistic script.

Found a mistake? Have a question or improvement idea? Let me know.

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