Text Diff

Compare two text blocks line by line and produce a compact, copyable diff for careful configuration review.

Converter Encoders & Utilities Runs in your browser

Result

Added lines
2
Removed lines
2
Unchanged lines
2
Line diff
  hostname edge-01
  interface ge-0/0/0
+  description ISP-PRIMARY
+  mtu 9000
-  description ISP-A
-  mtu 1500
Lines beginning with + were added; lines beginning with - were removed. This is an LCS line diff, not a semantic configuration parser.

About Text Diff

Compare configuration fragments, logs or notes without uploading them. The longest-common-subsequence algorithm preserves stable matching lines and presents additions and removals in a copyable result for careful operational review.

Line-oriented comparison

This tool compares complete lines, which makes configuration and log changes easy to review. It does not attempt to understand vendor syntax or hide whitespace changes.

Reviewing configuration changes

A text diff shows what changed, not whether the change is safe. Review surrounding hierarchy, default behaviour and platform syntax, then validate the candidate on the device or in a lab. Large blocks that move position may appear as removal plus addition even when their content is identical. Normalise generated timestamps or counters first when they would otherwise hide the operationally meaningful differences. Keep the original inputs alongside an approved change record when auditability matters.

Common use cases

  • Review a proposed network configuration change.
  • Compare two command outputs or logs.
  • Check generated text before and after an edit.

Edge cases and gotchas

  • Diff output is evidence for review, not proof that a configuration is correct or complete. Validate syntax, dependencies, order of operations and rollback behaviour on the target platform before applying any displayed change.

Frequently asked questions

Why is a large comparison rejected?
The exact LCS algorithm uses a matrix; the safety limit prevents excessive browser memory use. Split very large files into meaningful sections or use a streaming command-line diff when full-file scale exceeds the browser-oriented limit.
Are whitespace changes visible?
Yes. The comparison preserves line content exactly, so indentation and trailing characters may make otherwise similar lines appear changed.