REGEX帮助在标题中插入字符串

Question

我想在youtube的外发Cookie中插入安全首选项PREF=f2=8000000。有人可以请求正则表达式的帮助。如果没有它，请参阅下面的Cookie标题：

原始

SID=DQAAAOYAAABOR9H2kgqMkq1kw7rbRguqB6DNJPQxTP0zN4grw27QbTf_vzBKkiXPCE6Jof7kVtt8RrY72G8tV6LyolxU5rQNQwYtuJunHZ__7ueW4lkiZ89vmnloUhw3nsrkrg4QQIdvMhhys4ubR2yjWwqq6SYK4yL0LNq2HRP3UD5cGzDA_CQ_Vxn9g1tAdrZpcn5aQCOctWLrRV-cG23Rz3A6CH-2Fvfqt_VdX1QqBio5hiY6BD5SLFKzQr9hsgPQ61pY_bA2hgSzphPA8Ui0l4wdru-zG2jwlJ3tbtJ3dq3QIdoVHnmfVxt8rICS0GBun3iltVY; HSID=ANIIq2v5699ch1oGG; APISID=xXQlULDSZ9YV9cWf/Ax_rCe3I9FzrH0bDA; VISITOR_INFO1_LIVE=m46yOEoBrtU; LOGIN_INFO=9f010d0f2ad7425d84ae06a16d0aa294c34AAAB7IjgiOiAxMzc0NDk3NjUxODksICI3IjogMTM5MTUxMzA4MCwgIjYiOiBmYWxzZSwgIjUiOiAwLCAiNCI6ICJHQUlBIiwgIjMiOiAzMzAxNDc1ODUsICIyIjogIlk0cTlxY2pPaUo1RzN4VThGWEl1dHc9PSIsICIxIjogMX0=; PREF=fv=12.0.0&f1=10000000&al=en-GB; YSC=Qf6d6pKHmTQ; ACTIVITY=1391513121453

（参见最后包含的PREF = f2 = 8000000。）

所需

SID=DQAAAOYAAABOR9H2kgqMkq1kw7rbRguqB6DNJPQxTP0zN4grw27QbTf_vzBKkiXPCE6Jof7kVtt8RrY72G8tV6LyolxU5rQNQwYtuJunHZ__7ueW4lkiZ89vmnloUhw3nsrkrg4QQIdvMhhys4ubR2yjWwqq6SYK4yL0LNq2HRP3UD5cGzDA_CQ_Vxn9g1tAdrZpcn5aQCOctWLrRV-cG23Rz3A6CH-2Fvfqt_VdX1QqBio5hiY6BD5SLFKzQr9hsgPQ61pY_bA2hgSzphPA8Ui0l4wdru-zG2jwlJ3tbtJ3dq3QIdoVHnmfVxt8rICS0GBun3iltVY; HSID=ANIIq2v5699ch1oGG; APISID=xXQlULDSZ9YV9cWf/Ax_rCe3I9FzrH0bDA; VISITOR_INFO1_LIVE=m46yOEoBrtU; LOGIN_INFO=9f010d0f2ad7425d84ae06a16d0aa294c34AAAB7IjgiOiAxMzc0NDk3NjUxODksICI3IjogMTM5MTUxMzA4MCwgIjYiOiBmYWxzZSwgIjUiOiAwLCAiNCI6ICJHQUlBIiwgIjMiOiAzMzAxNDc1ODUsICIyIjogIlk0cTlxY2pPaUo1RzN4VThGWEl1dHc9PSIsICIxIjogMX0=; PREF=f2=8000000&f1=10000000&fv=12.0.0&al=en-GB; YSC=Qf6d6pKHmTQ; ACTIVITY=1391513121453

Answer 1

在perl：

s/(.+PREF=)(.+)/$1f2=8000000&$2/