how does ` cat << EOF` work in bash?
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by hasen j
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Published on 2010-03-23T13:57:35Z
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2010/03/23
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I needed to write a script to enter multi-line input to a program (psql)
After a big of googling, I found the following syntax works:
cat << EOF | psql ---params
BEGIN;
`pg_dump ----something`
update table .... statement ...;
END;
EOF
This correctly concatenates all these strings and passes the result as an input to psql.
but I have no idea how/why it works, can some one please explain?
I'm referring mainly to cat << EOF, I know > outputs to a file, >> appends to a file, < reads input from file.
What does << exactly do?
And is there a man page for it?
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