假设有文件test.txt,想把test.txt文件第三列含有的good替换为bye,并把替换后的文件保存为test_bye.txt,只需要如下命令. test.txt go go good go my my go good bye my good bye test_bye.txt go go bye go my my go good bye my bye bye awk -F " " '{if ($3==good) $3=bye}1' test.txt > test_bye.t
就在近日,Facebook宣布开源了内部使用的C++底层库,总称folly,包括散列.字符串.向量.内存分配.位处理等,以满足大规模高性能的需求. 这里是folly的github地址:https://github.com/facebook/folly 在folly项目的Overview.md中,谈到了folly库的初衷: It complements (as opposed to competing against) offerings such as Boost and of course s
Update中使用表别名 select中的表别名: select * from TableA as ta update中的表别名: update ta from TableA as ta 如何用表中一列值替换另一列的所有值 不同表列替换: update ta set ta.key1 = tb.key2 from TableA as ta, TableB as tb where ta.key = tb.key 同一表列替换: update ta set ta.key1 = tb.key2 from