You can print memory as instructions or as data.
In the following example, the wi alias lists machine instructions before and after the current instruction. Note that the asterisk (*) marks the current instruction.
(idb) alias wi
wi ($curpc - 20)/10 i
(idb) wi
CompoundNode::CompoundNode(float, int): x_list.cxx
[line 105, 0x120002348] cpys $f17,$f17,$f0
[line 105, 0x12000234c] bis r31, r18, r8
[line 101, 0x120002350] bis r31, r19, r16
[line 101, 0x120002354] bis r31, r8, r17
[line 101, 0x120002358] bsr r26, IntNode::IntNode(int)
*[line 101, 0x12000235c] ldq r18, -32712(gp)
[line 101, 0x120002360] lda r18, 48(r18)
[line 101, 0x120002364] stq r18, 8(r19)
[line 101, 0x120002368] sts $f0, 24(r19)
[line 106, 0x12000236c] bis r31, r19, r0
(idb) $pc/10x
0x12000235c: 0x8038 0xa65d 0x0030 0x2252 0x0008 0xb653 0x0018 0x9813
0x12000236c: 0x0400 0x47f3
(idb) $pc/6xx
0x12000235c: 0xa65d8038 0x22520030 0xb6530008 0x98130018
0x12000236c: 0x47f30400 0x47f5041a
(idb) $pc/2X
0x12000235c: 0x22520030a65d8038 0x98130018b6530008
Use the x command to dump memory in various formats. The disassemble command also provides disassembling capability.
(idb) x /10i $pc
0x08052e8f <main+27>: pushl %edi
0x08052e90 <main+28>: leal -160(%ebp), %eax
0x08052e96 <main+34>: movl %eax, (%esp)
0x08052e99 <main+37>: call 0x0804c4c8 <_ZN4ListI4NodeEC1Ev>
0x08052e9e <main+42>: addl $0x4, %esp
0x08052ea1 <main+45>: movl $0x0, -156(%ebp)
0x08052eab <main+55>: pushl %edi
0x08052eac <main+56>: movl $0xc, (%esp)
0x08052eb3 <main+63>: call 0x0804c308 <_init+744>
0x08052eb8 <main+68>: addl $0x4, %esp
(idb) x /10xh $pc
0x8052e8f <main+27>: 0x8d57 0x6085 0xffff 0x89ff 0x2404 0x2ae8 0xff96 0x83ff
0x8052e9f <main+43>: 0x04c4 0x85c7
(idb) x /6xw $pc
0x8052e8f <main+27>: 0x60858d57 0x89ffffff 0x2ae82404 0x83ffff96
0x8052e9f <main+43>: 0x85c704c4 0xffffff64
(idb) x /2xg $pc
0x8052e8f <main+27>: 0x89ffffff60858d57 0x83ffff962ae824044
To examine individual registers, use the print command with the register name prepended with the dollar sign ($). Commands showing all (or a subset of) the registers are specific for the mode; see examples below.