Editing Dc (computer program) (section)

==Input/output==
To read a line from [[stdin]], use the <code>?</code> command. This evaluates the line as if it were a dc command, and so it is necessary that it be syntactically correct and presents a potential security problem because the <code>!</code> dc command enables arbitrary command execution.

As mentioned above, <code>p</code> prints the top of the stack with a newline after it. <code>n</code> pops the top of the stack and prints it without a trailing newline. <code>f</code> prints the entire stack with one entry per line.

dc also supports arbitrary input and output [[radix|radices]]. The <code>i</code> command pops the top of the stack and uses it for the input base. Hex digits must be in upper case to avoid collisions with dc commands and are limited to A-F. The <code>o</code> command does the same for the output base, but keep in mind that the input base affects the parsing of every numeric value afterwards so it is usually advisable to set the output base first. Therefore <code>10o</code> sets the output radix to the current input radix, but generally not to 10 (ten). Nevertheless <code>Ao</code> resets the output base to 10 (ten), regardless of the input base. To read the values, the <code>K</code>, <code>I</code> and <code>O</code> commands push the current precision, input radix and output radix on to the top of the stack.

As an example, to convert from hex to binary:

<syntaxhighlight lang="console">
$ echo 16i2o DEADBEEFp | dc
11011110101011011011111011101111
</syntaxhighlight>