$WARNING

%+ Similar to @+ , the %+ hash allows

ARGVOUT The special filehandle that points to the currently open output file when doing edit-in-place processing with -i. Useful when

$EFFECTIVE_USER_ID

$DEBUGGING

$FORMAT_FORMFEED

%^H The %^H hash provides the same scoping semantic as

$^W The current value of the warning switch, initially true if -w was used, false otherwise, but directly modifiable.

${^PREMATCH} This is similar to $` ($PREMATCH) except that it does not incur the performance

$> The effective uid of this process. For example: $<