如何检查字符串是否在Bash shell中有空格

Question

说一个字符串可能就像"ab''c''d".如何检查字符串中是否包含单/双引号和空格？

Answer 1

你可以在bash中使用正则表达式:

string="a b '' c '' d"
if [[ "$string" =~ \ |\' ]]    #  slightly more readable: if [[ "$string" =~ ( |\') ]]
then
   echo "Matches"
else
   echo "No matches"
fi

编辑:

由于上面显而易见的原因,最好将正则表达式放在变量中:

pattern=" |'"
if [[ $string =~ $pattern ]]

并且在双方括号内不需要引号.它们不能在右侧使用,或者正则表达式更改为文字字符串.

Answer 2

case "$var" in  
     *\ * )
           echo "match"
          ;;
       *)
           echo "no match"
           ;;
esac

Answer 3

[[ "$str" = "${str%[[:space:]]*}" ]] && echo "no spaces" || echo "has spaces"

Answer 4

你可以这样做,而不需要任何反斜杠或外部命令:

# string matching

if [[ $string = *" "* ]]; then
  echo "string contains one more spaces"
else
  echo "string doesn't contain spaces"
fi

# regex matching

re="[[:space:]]+"
if [[ $string =~ $re ]]; then
  echo "string contains one or more spaces"
else
  echo "string doesn't contain spaces"
fi

有关:

• 如何检查字符串是否包含Bash中的子字符串

Answer 5

string="a b '' c '' d"
if [ "$string" == "${string//[\' ]/}" ]
then 
   echo did not contain space or single quote
else
   echo did contain space or single quote
fi