在bash中,正则匹配(Regular Expression Matching)是一种强大的文本处理工具,它允许你根据特定的模式来搜索、匹配或替换文本。正则匹配的核心是元字符(Metacharacters)和模式(Patterns),这些元素定义了搜索和匹配的标准。 2. bash正则匹配的常用元字符和模式示例 bash中的正则匹配支持多种元字符和模式,以下是一些常用的示...
if [ "`id -nu`" = "$someuser" ] ; then echo "I love you madly, $someuser" fi 他无法提供理由。有一个吗?bash if-statement syntax 答案[[具有较少的惊喜,并且通常更安全使用。但是它不是可移植的 - POSIX 没有指定它的功能,只有一些 shell 支持它(除了 bash,我听说 ksh 也支持它)。...
Regular expressions in Bash aren’t just limited to matching and searching text, In simple terms, besides finding and searching for specific text, regular expressions in Bash can also help you swap and change text patterns. This is really useful when you need to make big changes to lots of ...
Many types of expression can be used to define the matching regex patterns. Some of the commonly used regular expressions and the uses of some expressions with the =~ operator are explained in this tutorial. Commonly Used Regular Expressions Expression Purpose . It is used to search the ...
Match lines matching the regular expression regexp. p Print the current pattern space. [root@jfht ~]#STR=12345 [root@jfht ~]#[ "$(sed -n "/^[0-9]\+$/p" <<< "$STR")" ] && echo "yes" yes [root@jfht ~]# [ "$(echo "$STR" | sed -n "/^[0-9]\+$/p")" ] &&...
number Match only the specified line number (whichincrements cumulatively across files, unless the -s option is specified on the command line)./regexp/ Match lines matching the regular expression regexp. cv@cv:~/myfiles$sed'2d'test.txt #example-1cv@cv:~/myfiles$sed'2,10d'test.txt #exam...
An atom is a regular expression enclosed in ‘()’ (matching a match for the regular expression), an empty set of ‘()’ (matching the null string)(!), a bracket expression (see below), ‘.’ (matching any single character), ‘^’ ...
Regular Expression Matching (REMATCH) isnum(){declare-rnum_re='^[0-9]+$'declare-roctal_re='^0(.+)'num_error="ok"if[[$1=~$num_re]];then if[[$1=~$octal_re]];thennum_error="$1is not a number, did you mean${BASH_REMATCH[1]}?"return1fi ...
the operator is used as a pattern and pattern matching is performed. When the `=~'operatorisused,thestringto the right of theoperator ismatchedasa regular expression. The&∧||operatorsdonotevaluate EXPR2ifEXPR1issufficient to determine the expression's value. ...
the operator is used as a pattern and pattern matching is performed. When the `=~'operator is used, the string to the right of the operatoris matched as a regular expression. The&& and || operatorsdonot evaluate EXPR2ifEXPR1 is sufficient to ...