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11-12-2006

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echome

hi , I got a script that I don't understand.

Code:

awk '{
command="echo "$1
command | getline echome
close(command)
print $0 "\t" echome
}' < user.list

It reads the file user.list
user.list

Code:

London	John
Bridge	Peter

and sends the stream to the awk command.

I don't understand what is echome and I can't find what it is on Internet.

Thanks to help me.

remid1985

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11-12-2006

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utility of getline here?

Hi everybody , I got a file user.list
user.list

Code:

London	John
Bridge	Peter
Denoyelle R�mi

I got a script

Code:

awk '{
 command="echo "$1
 command | getline echome
 close(command)
 print $0 "\t" echome
 }' < user.list

It just displays all the content of the record (print $0) , followed by the first field (echo $1).

Why we don't use

Code:

awk '{
 print $0,$1
 }' < user.list

. Is it exactly the same?

I know that command | getline echome . It reads each line and applies the command command to the variable echome.

Thanks you so much

remid1985

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11-12-2006

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Quote:

Originally Posted by remid1985

hi , I got a script that I don't understand.

Code:

awk '{
   # build a variable "command" by concatinating the string "echo "
   # and a value of the FIRST field of the current record, e.g. "London",
   # "Bridge" etc....
   command="echo "$1

   # "execute" the command by invoking the content of the variable "command"
   # "read" (getline) the stdout of the executed command into a variable "echome"  
   command | getline echome

   # "close" the openned stream to the execution of command "command" 
   close(command)

   # print/output of the currect record/line separated with a "TAB" and the
   # the value of the variable "echome"
   print $0 "\t" echome
}' < user.list

It reads the file user.list
user.list

Code:

London	John
Bridge	Peter

and sends the stream to the awk command.

I don't understand what is echome and I can't find what it is on Internet. Smilie

Smilie

Thanks to help me.

'echome' is a variable your read (getline) the output of the command ''echo $1" from.

I put the comments in your original code - hopefully it makes things clearER.

vgersh99

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11-12-2006

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Pls don't multi-post - threads merged.

vgersh99

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