ZBZCZD 对于更复杂的用例,例如用多个字符替换单个字符或用其他子字符串替换子字符串,仍然可以使用tr命令,但有必要合并并使用正则表达式 (RegEx) 来完成此类任务。 tr的另一个有用的命令选项是 squeeze 或-s选项,它可以用单个字符替换一系列字符或子字符串。 脚本示例: STR="ABBBCDDDDDE"echo"$STR"| tr-sBD Z...
do {do-while body} while (condition) for (variable assignment; condition; iteration process) {for body} 3.循环控制 break continue 4.AWK next 提前结束对本行的处理进而提前进入下一行的处理。 三)函数 1.bash 函数 function: 功能 把一段具有独立功能代码封装在一起,并给予命名;后续用到时,可直接通过...
Once a variable is set, it may be unset only by using the unset builtin command (see SHELL BUILTIN COMMANDS below). A variable may be assigned to by a statement of the form name=[value] If value is not given, the variable is assigned the null string. All values undergo tilde expansi...
Some systems use the message catalog selected by theLC_MESSAGESshell variable. Others create the name of the message catalog from the value of theTEXTDOMAINshell variable, possibly adding a suffix of ‘.mo’. If you use theTEXTDOMAINvariable, you may need to set theTEXTDOMAINDIRvariable to the...
String replaceFirst(String regex, String replacement) Replaces the first substring of this string that matches the given regular expression with the given replacement. Java中常用的正则表达式元字符 . 代表任意字符 ? 表示前面的字符出现0次或1次
mutt: fix use of regex in the glob context (63924e6) mutt: rewrite ${cur/#!/X} to X${cur:1} against patsub_replacement (6b8f82b) mutt: use _comp_dequote for safe eval (f98379d) openssl: avoid variable conflicts (a31906c) openssl: fix variable i leak (83844b7) perl: fix ...
StringreplaceFirst(Stringregex,Stringreplacement) Replacesthefirstsubstringofthisstringthatmatchesthe givenregularexpressionwiththegivenreplacement. Java中常用的正则表达式元字符 .代表任意字符 ?表示前面的字符出现0次或1次 +表示前面的字符出现1次或多次 *表示前面的字符出现0次或多次 {n}表示前面的字符出现正好n次...
If the string is translated and replaced, the replacement is double-quoted. PARAMETERS A parameter is an entity that stores values. It can be a name, a number, or one of the special characters listed below under Special Parameters. A variable is a parameter denoted by a name. A variable ...
Bash has a built-inparameter substitutionfeature that enables pattern matching and replacement. We can use this feature to remove all occurrences of quotation characters in our variable: $ echo "${var//[\"\'\`]/}" A1B2C,D3E4F,G5H6I ...
See regex tutorial sed Thesedcommand is a stream editor that performs text transformations on an input. Common use of this command is to replace expressions which takes the forms/regexp/replacement/gFor example, the following replaces all occurrences of the phrase "Hello" with "Hi". ...