Shell字符串截取、替换、删除
字符串截取
- 从左向右截取第一个//后的字符串
word=abcd-//master-01://httpab echo ${word#*//} # 输出:master-01://httpab
- 从左向右截取最后一个//后的字符串
word=abcd-//master-01://httpab echo ${word##*//} # 输出:httpab
- 从右向左截取第一个//后的字符串
word=abcd-//master-01://httpab echo ${word%//*} # 输出:abcd-//master-01:
- 从右向左截取最一个//后的字符串
word=abcd-//master-01://httpab echo ${word%%//*} # 输出:abcd-
- 截取位置 0 后 3 个字符
word=abcd-//master-01://httpab echo ${word:0:3} # 输出:abc
- 从位置 1 截取到末尾
word=abcd-//master-01://httpab echo ${word:1} # 输出:bcd-//master-01://httpab
- 从位置-1 截取到末尾，就是截取最后一个
word=abcd-//master-01://httpab echo ${word:(-1)} # 输出:b
字符串替换
- 从左到右，匹配第一个，替换//为 cd
word=abcd-//master-01://httpab echo ${word/\/\//cd} # 输出:abcd-cdmaster-01://httpab
- 将所有匹配的//替换为 cd
word=abcd-//master-01://httpab echo ${word//\/\//cd} # 输出:abcd-cdmaster-01:cdhttpab
- 前缀匹配，只匹配从位置 0 开始的字符
word=abcd-//master-01://httpab echo ${word/#ab/cd} # 输出:cdcd-//master-01://httpab # -不是前缀，会匹配失败 echo ${word/#-/cd} # 输出:abcd-cdmaster-01://httpab
- 后缀匹配，只匹配结尾字符
word=abcd-//master-01://httpab echo ${word/%http*/xy} # 输出:abcd-//master-01://xy echo ${word/%ab/xy} # 输出:abcd-//master-01://httpxy echo ${word/%ab*/xy} # 出现*，会从起始匹配 # 输出:xy
字符串删除
利用字符截取和替换，以及拼接可以实现删除字符的效果
- 删除前 3 个字符
word=abcd-//master-01://httpab echo ${word#*${word:0:3}} # 输出:d-//master-01://httpab
- 删除后 3 个字符
word=abcd-//master-01://httpab echo ${word%*${word:(-3)}} # 输出:abcd-//master-01://htt
- 删除第一个 ab
word=abcd-//master-01://httpab echo ${word/ab/} # 输出:cd-//master-01://httpab
- 删除所有 ab
word=abcd-//master-01://httpab echo ${word//ab/} # 输出:cd-//master-01://http
- 删除最后一个 ab
word=abcd-//master-01://httpabcd echo ${word%ab*}${word##*ab} # 输出:abcd-//master-01://httpcd
字符串 trim
利用 xargs 可以实现 trim
word=" hello wolrd " word=`echo $word | xargs` echo $word # 输出:hello wolrd