current_processes=`ps aux | grep "tempdir" | tail -3`
当我回应它时,它看起来像这样
echo $current_processes 19984 10089 17784
当我回声加双引号时,它看起来像这样：
echo "$current_processes" 19984 10089 17784
当我使用双引号但没有双引号时,为什么它会将这些放在新行上？
解决方法
Word Splitting
The shell scans the results of parameter expansion,command substitution,and arithmetic expansion that did not occur within
double quotes for word splitting.The shell treats each character of IFS as a delimiter,and splits the
results of the other expansions into words on these characters. If IFS
is unset,or its value is exactly,the default,
then any sequence of IFS characters serves to delimit words. If IFS
has a value other than the default,then sequences of the whitespace
characters space and tab are ignored at the beginning and end of the
word,as long as the whitespace character is in the value of IFS (an
IFS whitespace character). Any character in IFS that is not IFS white-
space,along with any adjacent IFS whitespace characters,delimits a
field. A sequence of IFS whitespace characters is also treated as a
delimiter. If the value of IFS is null,no word splitting occurs.
您可以使用echo“$IFS”|查看IFS的内容XXD.它会告诉你
00000000: 2009 0a0a ...
这意味着空格(0x20),制表符(0x09)和换行符(0x0a).第二个0x0a来自echo命令.
您可以通过将IFS设置为空字符串来避免此替换：
IFS="" echo "$current_processes" 19984 10089 17784
但我不建议这样做.
