Before the problem was to find a use awk combining features of the same line in the tutorial, the following link:
http://blog.chinaunix.net/uid-10540984-id-3022733.html
The main problem in this:
Awk '{the if ($1==x) {I=I "" $2} else {the if (NR> 1) I} {print; I=$0}; X=$1; Y=$2} 'file & lt; (echo)
Mainly behind & lt; (echo)
In does not add & lt; (echo), the last one I won't output, which means the & lt; (echo) instead of the END I} {print effect, then try & lt; (ls) found in the output the result of adding the ls, understand that this is appended at the end of the output of the contents,
Then thought that this echo will not print the variable output, but the test is not the case, when the last exist before the output with the I and the new variables, b will only output the I,
B no output,
So this & lt; (echo) specific what is the principle that hasn't been understood, without bosses can show just a little, thank you!