Visit Our UNIX and Linux User Community


The here document <<


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting The here document <<
# 1  
Old 12-14-2004
The here document <<

Hello,

I want to know the use of the here document with the << operator.
Tried to go through some books but the concept was not clear.

Please can any1 expalin me this with a simple example.

Thanks,
Rahul.
# 2  
Old 12-14-2004
ftp machine << EOF
cd dirName
put file1
quit
EOF


Above is an example where ftp reads commands till it finds EOF. Inorder for above example to work u have to have .netrc configured ( with out asking for passwd).
# 3  
Old 12-15-2004
2 more examples ..


#!/usr/bin/ksh

tr "[a-z]" "[A-Z]" <<EOF
hello world
EOF


cat > file1 <<EOF
abcdefghijklmanopqr
stuv
wxyz
EOF


cat file1
# 4  
Old 12-15-2004
More examples.

Can any1 give me any example for writing interactive programs using the here document.

Thanks,
Rahul.
# 5  
Old 12-15-2004
bhargav has already given you three examples of here document usage.

You say you want to write an "interactive" program using a here document? The very nature and purpose of a here document is to take away user interaction and provide automation.

If you have a specific requirement, then please post what it is you're trying to do.

Cheers
ZB
# 6  
Old 12-15-2004
Thanks i got it

Thanks to all of u,

Now i got the concept of the here document.

The idea is that interactive programs can take input from this here document without waiting for user input.
# 7  
Old 01-23-2006
hi....i understood why the here block is used...but i fail to understand the exact control flow behind it...i mean how does is work and what is the concept behind it? can u kindly throw some light on it? thanks again

Previous Thread | Next Thread
Test Your Knowledge in Computers #66
Difficulty: Medium
IT and cybersecurity risk management is based on the intersection of these three areas, criticality, vulnerability, and threat.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Fetch the value from Here Document

I have code like var="1" echo << EOF export `var="2"` EOF echo $var The value of var is printed here is 1 but it should be 2 Any error there? ---------- Post updated at 11:44 AM ---------- Previous update was at 10:33 AM ---------- Also tried var="1" echo var << EOF echo... (1 Reply)
Discussion started by: adisky123
1 Replies

2. Homework & Coursework Questions

HTML document

Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted! 1. The problem statement, all variables and given/known data: <HTML><HEAD><TITLE>Personal Web Page</TITLE></HEAD> <BODY BGCOLOR="WHITE"><H3> <CENTER>My Personal Page<HR>... (0 Replies)
Discussion started by: Larry_1
0 Replies

3. Shell Programming and Scripting

Here document inside a here document?

Can we use a here document inside a here document? Something like this ssh user@remotehost << REMOTE sudo vserver vsernamename enter << VSERVER perform actions on vserver. VSERVER REMOTE (6 Replies)
Discussion started by: mnanavati
6 Replies

4. Shell Programming and Scripting

Variables in HERE DOCUMENT

Here is my problem: can we set the variables in the HERE DOCUMENT? I have tried but failed. Any one has good comments please let me know. #!/bin/csh -f pbrun -u xmgbrk runshell <<! @ $num1 = `wc -l /home/tpltp/csh/scripts/who.csh` echo "$num1" if ( $num1 > 0 ) then echo $num1 | tee -a... (1 Reply)
Discussion started by: tpltp
1 Replies

5. Shell Programming and Scripting

Document

Plz can somebody give me the shell and perl scripting documents,i need to start the scrpts learning.now i know about the linux commands,but need help in putting the same in the scripting with do,if,while and also using diffrent commands in the scrpipts,pls help.. (3 Replies)
Discussion started by: satish.res
3 Replies

6. Shell Programming and Scripting

ssh and here document

Hi :) how can I use here doc to use ssh? I am facing a problem with the below script: #!/bin/bash ssh hosein@localhost << * 123456 * "123456" is my password Thanks (2 Replies)
Discussion started by: htabesh
2 Replies

7. Shell Programming and Scripting

here document not working

I tried doing ftp myhost <<HERE username password quit HERE but it doesnt work. Why? When I do ftp host, I always get prompted for username, and once I type that in I get prompted for password. But when I try doing it from here document it freezes. (2 Replies)
Discussion started by: JamesByars
2 Replies

8. UNIX for Dummies Questions & Answers

Teaching myself Here Document

I understand that a Here Document will redirect all of the lines between the beginning marker for the here document and the ending marker into the command specified just as if the text were coming from standard input. I am trying to understand the Here Document with this example: # Menu file... (3 Replies)
Discussion started by: ericelysia
3 Replies

9. Shell Programming and Scripting

echo with a here-document

I do not know how valid this post is, but here it is. I was writing a script for testing some development code that I had written. It involved many echo statements to redirect the output into a log file. Given the large number of echo statements, I took to this solution cat <<EOF >>... (2 Replies)
Discussion started by: vino
2 Replies

10. Shell Programming and Scripting

How to split a document

Hi.. Does anybody knows how can I split a file in N documents?? I have a document of more than 80,000 lines (it is generated in a dynamic way, sometimes has 80,000 others 30,000 , or 1000,000) Im trying tyo break this file in only 1 lines of commands but I want to break it in a N differents files... (2 Replies)
Discussion started by: gtapia
2 Replies

Featured Tech Videos