By default, GDB prints a value according to its data type. Sometimes this isn't what you want. For example, you might want to print a number in hex, or a pointer in decimal. Or you might want to view data in memory at a certain address as a character string or as an instruction. To do these things, specify an output format when you print a value.
The simplest use of output formats is to say how to print a value already computed. This is done by starting the arguments of the print command with a slash and a format letter. The format letters supported are:
(gdb) p/a 0x54320 $3 = 0x54320 <_initialize_vx+396>
For example, to print the program counter in hex (see Registers), type:
p/x $pc
To reprint the last value in the value history with a different format, you can use the print command with just a format and no expression. For example, p/x reprints the last value in hex.