.ig
	vhel4: version 1.2 of 11/8/83
	

	@(#)vhel4	1.2	(NSC)	11/8/83
..
.NH
INFORMATION HANDLING
.LP
.sh SORT
Sort or merge ASCII files line-by-line.
No limit on input size.
.op
Sort up or down.
.op
Sort lexicographically or on numeric key.
.op
Multiple keys located by delimiters or by character position.
.op
Can sort upper case together with lower into dictionary order.
.op
Optionally suppress duplicate data.
.sh TSORT
Topological sort \(em converts a partial order into a total order.
.sh UNIQ
Collapse successive duplicate lines
in a file into one line.
.op
Publish lines that were originally unique,
duplicated, or both.
.op
Can give redundancy count for each line.
.sh TR
Do one-to-one character translation according to
an arbitrary code.
.op
Can coalesce selected repeated characters.
.op
Can delete selected characters.
.sh DIFF
Report line changes, additions and deletions necessary to bring two files
into agreement.
.op
Can produce an editor script to convert one file into another.
.op
A variant compares two new versions against one old one.
.sh BDIFF
Process files too big for DIFF.
.sh DIFF3
Compare three files and publish disagreeing ranges of text.
.sh COMM
Identify common lines in two sorted files.
Output in up to 3 columns shows lines present in first file only,
present in both, and/or present in second only.
.sh GREP
Print all lines in a file that satisfy
a pattern as used in the editor ED.
.op
Can print all lines that fail to match.
.op
Can print count of hits.
.op
Can print first hit in each file.
.sh WC
Count the lines, ``words'' (blank-separated strings) and characters in a file.
.sh SED
Stream-oriented version of ED.
Can perform a sequence of editing operations on
each line of an
input stream of unbounded length.
.op
Lines may be selected by address or range of addresses.
.op
Control flow and conditional testing.
.op
Multiple output streams.
.op
Multiline capability.
.sh AWK
Pattern scanning and processing language.
Searches input for patterns, and
performs actions on each line of input that satisfies
the pattern.
.op
Patterns include regular expressions,
arithmetic and lexicographic conditions,
boolean combinations and ranges of these.
.op
Data treated as string or numeric as appropriate.
.op
Can break input into fields;
fields are variables.
.op
Variables and arrays (with non-numeric subscripts).
.op
Full set of arithmetic operators and control flow.
.op
Multiple output streams to files and pipes.
.op
Output can be formatted as desired.
.op
Multiline capabilities.
.sh SCCS
Source Code Control System is a collection of commands for controlling
changes to files of text, typically the source code of programs or the
text of documents.
.op
Keep track of updates to a file.  All versions of a file are available
for viewing or editing.
.op
Create new SCCS files and change parameters of existing ones.
.op
Record in comments why a file was changed.
.op
Merge two versions of a file.
.op
List differences of two version of a file.
.op
Print history of changes to a file.
.op
Undo changes to a file.
.op 
State which files are currently being worked on.
