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select always the first row

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# 1  
Old 10-14-2010
select always the first row
Hi, I have an output like this:

Code:
#CMD

Output:
user1
user2
user3
user4

How can I select ONLY the first row?

Thanks
# 2  
Old 10-14-2010
Code:
man head

# 3  
Old 10-14-2010
Code:
CMD | head -1

# 4  
Old 10-14-2010
'line' is very good at this:
  • not waiting for even the first byte of the second line, saving delay if the flow is intermittent.
  • leaving all following lines on the fd for other processes sharing it to read, which can save you a lot of CPU on a big file.
    Code:
    . . . |(
 line >header_file.txt
 whatever_cmd_reading_rest
 )

In ksh, 'read', as in:
Code:
. . . | read l
echo $l

but
  • this trims white space
  • ksh reads more than the first line, since stdin is a FILE*.
# 5  
Old 10-14-2010
OK, thanks!
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