diff --git a/docs/dj.1 b/docs/dj.1
index 4b0b5b1..43c2750 100644
--- a/docs/dj.1
+++ b/docs/dj.1
@@ -15,13 +15,13 @@ dj
 .RB [ -a\ byte ]
 .RB [ -c\ count ]
 
-.RB [ -i\ input_file ]
-.RB [ -b\ input_block_size ]
-.RB [ -s\ input_offset ]
+.RB [ -i\ file ]
+.RB [ -b\ block_size ]
+.RB [ -s\ offset ]
 
-.RB [ -o\ output_file ]
-.RB [ -B\ output_block_size ]
-.RB [ -S\ output_offset ]
+.RB [ -o\ file ]
+.RB [ -B\ block_size ]
+.RB [ -S\ offset ]
 .\"
 .SH DESCRIPTION
 
@@ -39,25 +39,25 @@ immediately subsequent to the specified byte.
 .\"
 .SH OPTIONS
 
-.IP \fB-i\fP
+.IP \fB-i\fP\ \fIfile\fP
 Takes a file path as an argument and opens it for use as an input.
-.IP \fB-b\fP
+.IP \fB-b\fP\ \fIblock_size\fP
 Takes a numeric argument as the size in bytes of the input buffer, the default
 being 1024.
-.IP \fB-s\fP
+.IP \fB-s\fP\ \fIoffset\fP
 Takes a numeric argument as the number of bytes to skip into the input
 before starting to read. If the standard input is used, bytes read to this point
 are discarded.
-.IP \fB-o\fP
+.IP \fB-o\fP\ \fIfile\fP
 Takes a file path as an argument and opens it for use as an output.
-.IP \fB-B\fP
+.IP \fB-B\fP\ \fIblock_size\fP
 Does the same as
 .B -b
 but for the output buffer.
-.IP \fB-S\fP
+.IP \fB-S\fP\ \fIoffset\fP
 Seeks a number of bytes through the output before starting to write from
 the input. If the output is a stream, null characters are printed.
-.IP \fB-a\fP
+.IP \fB-a\fP\ \fIbyte\fP
 Accepts a single literal byte with which the input buffer is padded in the event
 of an incomplete read from the input file.
 .IP \fB-A\fP
@@ -65,7 +65,7 @@ Specifying this option pads the input buffer with null bytes in the event of an
 incomplete read. This is equivalent to specifying
 .B -a
 with a null byte instead of a character.
-.IP \fB-c\fP
+.IP \fB-c\fP\ \fIcount\fP
 Specifies a number of reads to make. The default is 0, in which case the
 input is read until a partial or empty read is made.
 .IP \fB-d\fP
diff --git a/docs/fop.1 b/docs/fop.1
index d777c68..b96033a 100644
--- a/docs/fop.1
+++ b/docs/fop.1
@@ -22,7 +22,7 @@ Performs operations on specified fields in data read from the standard input.
 .\"
 .SH OPTIONS
 
-.IP \fB-d\fP
+.IP \fB-d\fP\ \fIdelimiter\fP
 Sets a delimiter by which the input data will be split into fields. The default
 is an ASCII record separator.
 .\"
diff --git a/docs/mm.1 b/docs/mm.1
index 735f9df..2916aa7 100644
--- a/docs/mm.1
+++ b/docs/mm.1
@@ -24,10 +24,10 @@ Catenate input files and write them to the start of each output file or stream.
 Opens subsequent outputs for appending rather than updating.
 .IP \fB-e\fP
 Use the standard error as an output.
-.IP \fB-i\fP
+.IP \fB-i\fP\ \fIinput\fP
 Opens a path as an input. If one or more of the input files is \(lq-\(rq or if
 no inputs are specified, the standard input shall be used.
-.IP \fB-o\fP
+.IP \fB-o\fP\ \fIoutput\fP
 Opens a path as an output. If one or more of the output files is \(lq-\(rq or if
 no outputs are specified, the standard output shall be used.
 .IP \fB-u\fP
diff --git a/docs/swab.1 b/docs/swab.1
index e589c10..42eef95 100644
--- a/docs/swab.1
+++ b/docs/swab.1
@@ -22,7 +22,7 @@ Swap the latter and former halves of a block of bytes.
 
 .IP \fB-f\fP
 Ignore SIGINT signal.
-.IP \fB-w\fP
+.IP \fB-w\fP\ \fIword_size\fP
 Configures the word size; that is, the size in bytes of the block size on which
 to operate. The default word size is 2. The word size must be cleanly divisible
 by 2, otherwise the block of bytes being processed can\(cqt be halved.
diff --git a/src/dj.c b/src/dj.c
index 3885012..beafde8 100644
--- a/src/dj.c
+++ b/src/dj.c
@@ -314,8 +314,8 @@ static int
 usage(void){
 
 	fprintf(stderr, "Usage: %s [-AdfHqQ] [-a byte] [-c count]\n"
-		"\t[-i input_file] [-b input_block_size] [-s input_offset]\n"
-		"\t[-o output_file] [-B output_block_size] [-S output_offset]\n",
+		"\t[-i file] [-b block_size] [-s offset]\n"
+		"\t[-o file] [-B block_size] [-S offset]\n",
 		program_name);
 
 	return EX_USAGE;