asterisk*CLI> show functions
Installed Custom Functions:
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FIELDQTY*CLI>   (Count the fields, with an arbitrary delimiter) [FIELDQTY(<varname>,<delim>)]
GROUP_MATCH_COUNT       (Calculates the group count for all groups that match the specified pattern. Uses standard regular expression matching (see regex(7)).)      [GROUP_MATCH_COUNT(groupmatch[@category])]
GROUP_COUNTI>   (Calculates the group count for the specified group, or uses the current channel's group if not specifed (and non-empty).)   [GROUP_COUNT([groupname][@category])]
SIP_HEADERLI>   (Gets or sets the specified SIP header) [SIP_HEADER(<name>)]
CHECK_MD5CLI>   (Checks an MD5 digest. Returns 1 on a match, 0 otherwise)       [CHECK_MD5(<digest>,<data>)]
MD5erisk(Computes an MD5 digest)        [MD5(<data>)]
CDRerisk(Gets or sets a CDR variable; option 'r' searches the entire stack of CDRs on the channel)      [CDR(<name>[|options])]
LENerisk(Returns the length of the arguments given)     [LEN(<string>)]
ENVerisk(Gets or sets the environment variable specified)       [ENV(<envname>)]
ifterisk(Conditional: Returns the data following '?' if true else the data following ':')       [if(<expr>?<true>:<false>)]
existssk(Existence Test: Returns 1 if exists, 0 otherwise)      [exists(<data>)]
isnullsk(NULL Test: Returns 1 if NULL or 0 otherwise)   [isnull(<data>)]
regexisk(Regular Expression: Returns 1 if data matches regular expression.)     [regex("<regular expression>" <data>)]
asterisk*CLI>