shell#字符串

一丶字符串处理

1.字符串截取

a=abcdefg

echo ${a:1:1} ===b     //${变量:从第几位开始:截几位}

echo ${a:3:3} ===def

2.字符串替换

${变量名/old/new}

abc

echo ${a/b/8}

a8c

aabbcc

echo ${a/b/8}

aa8bcc

echo ${a//b/8}

aa88cc

3.字符串删除

${变量名#}  从左往右删除

${变量名##*}

${变量名%}从右往左删除

${变量名%%*}