CODEWITHSUNDEEP
bash
Judking
Judking

Reputation: 6371

What's this mean in a sh script?

I intend to enter the hive shell(as below) in a sh script and do some HQL request.

$ hive
Hive history file=/tmp/admin/hive_job_log_admin_201309110939_570764_8012_1eecdf83_1dd4da6d.txt
hive>

Then I got a script which could just work the way I want. The code snippet of sh script is as follows:

#!/bin/bash

#HQL
/home/hive/hive/bin/hive -u root -p root <<EOF
show tables;
EOF

But I don't know what exactly does <<EOF and the last EOF mean. Could anyone just give me a specific explanation on this? Thanks a lot!

Upvotes: 0

Views: 205

Answers (2)

poohdedoo
poohdedoo

Reputation: 1268

EOF is just a common heredoc delineator it can be anything not just EOF it can be MyEOF ect. If you declare it like MyEOF then it will use the string MyEOF as a standard input and you can specify $MyEOF as variables which later you can use its contents as stdin. As Johnsyweb mentioned this is called a herestring, as it uses a short string in contrast to a whole block, as in a heredoc.

Upvotes: 0

johnsyweb
johnsyweb

Reputation: 141780

This is called "here document" (also here-document, heredoc, hereis, here-string or here-script) syntax.

<<EOF
show tables;
EOF

Yields the text:

show tables;

For more information see the tag wiki for .

Upvotes: 4

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