练习题:http://blog.chinaunix.net/uid-10540984-id-3086644.html
cat file:
awk ‘ {s=$1;printf s;for (i=2;i<=length($0)-1;i++) if($i!=s) printf $i;print ‘\n‘}‘ test.txt
人家的答案:awk ‘{a=$1;gsub(" ?"a,"");print a""$0}‘ file
原文:http://www.cnblogs.com/amandaysu/p/3982655.html