A collection of handy user utilities for the Erlang shell.

Usage

Debugger helper functions

dbg(c)              %   clear all traces = stop tracing
dbg(c, T)           %   schedule clearing all traces after T msec

dbg(M)              %   trace on module M
dbg(M, O)           %   trace on module M with options O
dbg(M, F)           %   trace on function M:F
dbg(M, F, O)        %   trace on function M:F with options O
dbg(M, F, A)        %   trace on function M:F(A)
dbg(M, F, A, O)     %   trace on function M:F(A) with options O
dbgo()              %   print debugging options help
dbgt(File)          %   print trace data read from File

The options for debugging are:

c                   %   clear
r                   %   show return trace (including exceptions)
l                   %   trace on local functions
lr                  %   trace on local functions with return trace (including exceptions)

Benchmarking helper functions

tc(N, F)            % evaluate F N times and return same result as function tc(N, M, F, A)
tc(N, M, F, A)      % evaluate M:F(A) N times and return [{total, <total run time>},
                                                          {arithmetic_mean, <mean>},
                                                          {last_result, <result>}]

tca(N, F)           % evaluate F N times and return same result as function tca(N, M, F, A)
tca(N, M, F, A)     % evaluate M:F(A) N times and return stats as below:

                    (if you have bear library in the ERL_LIB path)
                    
                    [{min,10137},
                     {max,12630},
                     {arithmetic_mean,11537.6},
                     {geometric_mean,11516.435993993891},
                     {harmonic_mean,11494.89018688898},
                     {median,11374},
                     {variance,532961.6000000001},
                     {standard_deviation,730.0421905616141},
                     {skewness,-0.30488239045264337},
                     {kurtosis,-0.9594953873072507},
                     {percentile,[{50,11374},
                                  {75,12114},
                                  {90,12230},
                                  {95,12630},
                                  {99,12630},
                                  {999,12630}]},
                     {histogram,[{11337,4},{12537,5},{14137,1}]},
                     {n,10}]
                     
                 (or simplier form if bear library is not available)
                    
                    [{min,10137},
                     {max,12630},
                     {arithmetic_mean,11537.6},
                     {median,11374},
                     {n,10}]

Other helper functions

p(Term)             % print term using io:format("~p~n", [Term])
l()                 % load all changed modules on current node
nl()                % load all changed modules on all known nodes
mm()                % list modified modules
mk()                % compile modules specified by Emakefile (if exists) or in current directory
dmfa()              % run M:F(A1,...,An) on all visible nodes
decompile(M)        % decompile module or beam file

Building and installation

Run make and put the line below into ~/.erlang file to enable utilities:

code:load_abs("/path/to/erlang_user_utils/user_default").

See also http://erlang.org/doc/man/shell_default.html