如何从数据表中的列子集中提取唯一行？(How do I extract the unique rows from a subset of columns in a data table?)

 看起来你有一个JSON字符串。 请记住，JSON是无序的 ，因此如果下一次以不同的顺序出现字符串，则大多数sed，awk，cut解决方案将失败。 
 
 使用JSON解析器是最健壮的。 
 
 您可以将ruby与其JSON解析器库一起使用： 
 
$ echo "$fullToken" | ruby -r json -e 'p JSON.parse($<.read)["token"];'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
 
 或者，如果您不想要引用的字符串（这对Bash很有用）： 
 
$ echo "$fullToken" | ruby -r json -e 'puts JSON.parse($<.read)["token"];'
l0ng_Str1ng.of.d1fF3erent_charAct3rs
 
 或者用jq ： 
 
$ echo "$fullToken" | jq '.token'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
 
 即使JSON字符串的顺序不同，所有这些解决方案都将起作用： 
 
$ echo '{"type":"APP","token":"l0ng_Str1ng.of.d1fF3erent_charAct3rs"}' | jq '.token'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
$ echo '{"token":"l0ng_Str1ng.of.d1fF3erent_charAct3rs", "type":"APP"}' | jq '.token'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
 
 但是知道你应该使用JSON解析器，你也可以在Gnu Grep中使用一个看起来很好的PCRE： 
 
$ echo "$fullToken" | grep -oP '(?<="token":)"([^"]*)'
 
 或者在Perl中： 
 
$ echo "$fullToken" | perl -lane 'print $1 if /(?<="token":)"([^"]*)/'
 
 如果字符串的顺序不同，这两个也可以工作。 
 
 或者，使用POSIX awk： 
 
$ echo "$fullToken" | awk -F"[,:}]" '{for(i=1;i<=NF;i++){if($i~/"token"/){print $(i+1)}}}'
 
 或者，使用POSIX sed，您可以： 
 
$ echo "$fullToken" | sed -E 's/.*"token":"([^"]*).*/\1/'
 
 这些解决方案最强（使用JSON解析器）更脆弱（sed）。 但是我在那里的sed解决方案比其他解决方案更好，因为它将支持JSON字符串中的键，值的顺序不同。 
 
 
 Ps：如果你想从一行中删除引号，这对sed来说是一个很好的工作： 
 
$ echo '"quoted string"' 
"quoted string"
$ echo '"quoted string"' | sed -E 's/^"(.*)"$/UN\1/'
UNquoted string

It looks like you have a JSON string there. Keep in mind that JSON is unordered, so most sed, awk, cut solutions will fail if you string comes next time in a different order. 
 
It is most robust to use a JSON parser. 
 
You could use ruby with its JSON parser library:
 
$ echo "$fullToken" | ruby -r json -e 'p JSON.parse($<.read)["token"];'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
 
Or, if you don't want the quoted string (which is useful for Bash):
 
$ echo "$fullToken" | ruby -r json -e 'puts JSON.parse($<.read)["token"];'
l0ng_Str1ng.of.d1fF3erent_charAct3rs
 
Or with jq:
 
$ echo "$fullToken" | jq '.token'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
 
All these solutions will work even if the JSON string is in a different order:
 
$ echo '{"type":"APP","token":"l0ng_Str1ng.of.d1fF3erent_charAct3rs"}' | jq '.token'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
$ echo '{"token":"l0ng_Str1ng.of.d1fF3erent_charAct3rs", "type":"APP"}' | jq '.token'
"l0ng_Str1ng.of.d1fF3erent_charAct3rs"
 
But KNOWING that you SHOULD use a JSON parser, you can also use a PCRE with a look behind in Gnu Grep:
 
$ echo "$fullToken" | grep -oP '(?<="token":)"([^"]*)'
 
Or in Perl:
 
$ echo "$fullToken" | perl -lane 'print $1 if /(?<="token":)"([^"]*)/'
 
Both of those also work if the string is in a different order.
 
Or, with POSIX awk:
 
$ echo "$fullToken" | awk -F"[,:}]" '{for(i=1;i<=NF;i++){if($i~/"token"/){print $(i+1)}}}'
 
Or, with POSIX sed, you can do:
 
$ echo "$fullToken" | sed -E 's/.*"token":"([^"]*).*/\1/'
 
Those solutions are presented strongest (use a JSON parser) to more fragile (sed). But the sed solution I have there is better than the other because it will support the key, values in the JSON string being in different order. 
 
 
Ps: If you want to remove the quotes from a line, that is a great job for sed:
 
$ echo '"quoted string"' 
"quoted string"
$ echo '"quoted string"' | sed -E 's/^"(.*)"$/UN\1/'
UNquoted string