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Header Format Comparison

LicenseOps supports 5 header formats. This guide helps you choose the right one.

Quick Comparison​

FormatLinesUse When
spdx (2-line)2Default choice. Clean, machine-readable, widely recognized.
spdx (1-line)1SPDX tag without per-file copyright (e.g. Linux kernel style).
reuse2FSFE REUSE compliance required.
apache-long14Apache Foundation projects or projects that require the full boilerplate.
gpl-long14FSF/GNU projects that require the full GPL/LGPL/AGPL boilerplate.
customVariesOrganization-specific headers that don't fit any built-in format.

Side-by-Side Examples​

All examples below use Go (// comments), Apache-2.0 license, copyright holder Acme Corp.

spdx (2-line, default)​

// Copyright 2026 Acme Corp
// SPDX-License-Identifier: Apache-2.0
  • Pros: Short, clean, machine-parseable by all SPDX-aware tools
  • Cons: Doesn't include license terms — relies on a root LICENSE file
  • Config: format: spdx (or omit — it's the default)

spdx (1-line)​

// SPDX-License-Identifier: Apache-2.0
  • Pros: Minimal footprint, one line per file
  • Cons: No per-file copyright attribution
  • Config: format: spdx with copyright-holder omitted

reuse​

// SPDX-FileCopyrightText: 2026 Acme Corp
// SPDX-License-Identifier: Apache-2.0
  • Pros: FSFE REUSE standard, explicitly machine-readable copyright line
  • Cons: Less common outside European open-source projects
  • Config: format: reuse

apache-long​

// Copyright 2026 Acme Corp
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
  • Pros: Legally self-contained, no dependency on root LICENSE file
  • Cons: 14 lines of boilerplate in every file
  • Config: format: apache-long (requires license: Apache-2.0)

gpl-long​

// Copyright 2026 Acme Corp
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
  • Pros: FSF-recommended, legally self-contained
  • Cons: Long, only valid for GPL-family licenses
  • Config: format: gpl-long (requires a GPL/LGPL/AGPL license)
  • Variants: Automatically selects GPL, LGPL, or AGPL wording based on the license ID

Supported Licenses per Format​

FormatValid Licenses
spdxAny SPDX ID or expression
reuseAny SPDX ID or expression
apache-longApache-2.0 only
gpl-longGPL-2.0-only, GPL-2.0-or-later, GPL-3.0-only, GPL-3.0-or-later, LGPL-*, AGPL-*
customAny SPDX ID or expression

Comment Style by Language​

Each format adapts to the file's comment syntax automatically.

Line comment languages (//, #, --):

Headers are written with the line comment prefix on each line.

Block comment only languages (CSS /* */, HTML <!-- -->):

Headers are wrapped in a block comment:

/*
 Copyright 2026 Acme Corp
 SPDX-License-Identifier: Apache-2.0
*/

For SPDX 1-line mode, a single-line block comment is used:

/* SPDX-License-Identifier: Apache-2.0 */

Migration Between Formats​

LicenseOps handles format migration automatically. When you run fix with a different format than what's currently in the files, it:

  1. Detects and strips the old header (any known format)
  2. Inserts the new header in the target format
# Files currently have apache-long headers
# Migrate to SPDX short:
lops fix -f spdx -l Apache-2.0 -o "Acme Corp" .

No manual cleanup needed — the old boilerplate is fully removed and replaced.

tip

Use lops fix --dry-run to preview what migration would do before modifying files.

warning

Migration fully removes the old header. If your old header contained custom text (e.g. additional notices), it will be lost. Use --dry-run first to verify.

See Also​