Linux字符串处理.docx

一、构造字符串直接构造STR_ZERO=helloSTR_FIRST=i am a stringSTR_SECOND=success重复多次#repeat the first parm($1) by $2 timesstrRepeat(){local x=$2if [ $x == ]; thenx=0filocal STR_TEMP=while [ $x -ge 1 ];doSTR_TEMP=`printf %s%s $STR_TEMP $1`x=`expr $x - 1`doneecho $STR_TEMP}举例：STR_REPEAT=`strRepeat $USER_NAME 3`echo repeat = $STR_REPEAT二、赋值与拷贝直接赋值与构造字符串一样USER_NAME=terry从变量赋值ALIASE_NAME=$USER_NAME三、联接直接联接两个字符串STR_TEMP=`printf %s%s $STR_ZERO $USER_NAME`使用printf可以进行更复杂的联接四、求长求字符数(char)COUNT_CHAR=`echo $STR_FIRST | wc -m`echo $COUNT_CHAR求字节数(byte)COUNT_BYTE=`echo $STR_FIRST | wc -c`echo $COUNT_BYTE求字数(word)COUNT_WORD=`echo $STR_FIRST | wc -w`echo $COUNT_WORD五、比较相等比较str1 = str2不等比较str1 != str2举例：if [ $USER_NAME = terry ]; thenecho I am terryfi小于比较#return 0 if the two string is equal, return 1 if $1 $2, else 2strCompare() { local x=0 if [ $1 != $2 ]; then x=2 localTEMP=`printf %s\n%s $1 $2` local TEMP2=`(echo $1; echo $2) |sort` if [ $TEMP = $TEMP2 ]; then x=1 fi fi echo $x }六、测试判空-z str判非空-n str是否为数字# return 0 if the string is num, otherwise 1strIsNum(){local RET=1if [ -n $1 ]; thenlocal STR_TEMP=`echo $1 | sed s/[0-9]//g`if [ -z $STR_TEMP ]; thenRET=0 fifiecho $RET}举例：if [ -n $USER_NAME ]; thenecho my name is NOT emptyfiecho `strIsNum 9980`七、分割以符号＋为准，将字符分割为左右两部分使用sed举例：命令 date --rfc-3339 seconds 的输出为2007-04-14 15:09:47+08:00取其＋左边的部分date --rfc-3339 seconds | sed s/+[0-9][0-9]:[0-9][0-9]//g输出为2007-04-14 15:09:47取+右边的部分date --rfc-3339 seconds | sed s/.*+//g输出为08:00以空格为分割符的字符串分割使用awk举例：STR_FRUIT=Banana 0.89 100取第3字段echo $STR_FRUIT | awk { print $3; }八、子字符串字符串1是否为字符串2的子字符串# return 0 is $1 is substring of $2, otherwise 1strIsSubstring(){local x=1case $2 in*$1*) x=0;;esacecho $x}