bash/shell的字符串trim实现

#!/bin/sh trim() {     trimmed=$1     trimmed=${trimmed%% }     trimmed=${trimmed## }     echo $trimmed } 测试： a=" x x " b=" b b" c="c c " echo "=$a=" echo "=$b=" echo "=$c=" a=$(trim $a) b=$(trim $b) c=$(trim $c) echo "=$a=" echo "=$b=" echo "=$c=" 输出： = x x = = b b= =c c = =x= =b= =c=