Question

I’m trying to run a jruby -S rake db:migrate operation.

This results in an error, which exceeds the number of lines my bash terminal holds, so I can’t see the most relevant lines, and I’m stuck with ~1000 lines of:

....
org/jruby/runtime/Block.java:89:in `call'
org/jruby/RubyProc.java:261:in `call'
org/jruby/RubyProc.java:249:in `call19'
org/jruby/RubyProc$INVOKER$i$0$0$call19.gen:-1:in `call'
org/jruby/internal/runtime/methods/DynamicMethod.java:216:in `call'
org/jruby/internal/runtime/methods/DynamicMethod.java:212:in `call'
org/jruby/runtime/callsite/CachingCallSite.java:202:in `call'
org/jruby/ast/CallTwoArgNode.java:59:in `interpret'
....

I tried jruby -S rake db:migrate > migrate.out but the error messages still appear on my terminal and the contents of migrate.out is

==  ChangeFieldsOnFoo: migrating ========================================
-- remove_column(:foos, :bar)

Surely there must be a way to read this error message!

Answer 1

Tie stderr(2) to stdout(1) using 2>&1 and pipe (|) the output through a “pager” such as less to keep it on the screen until you have finished with it:

jruby -S rake db:migrate 2>&1 | less