janus-cli

janus-cli is a small Bash CLI tool for recursive literal find/replace operations across:

• text file contents
• filenames
• directory names

It is intended for controlled site or project renames, such as changing an old virtual host to a new hostname across Apache vhost files, webroots, and application config files.

Safety warning!

This script can and will do "very bad things" to the files you love if you do not use it correctly, and cannot be guaranteed to not do so even if you do. This script could possibly call your cat terrible names, even if you do not have a cat. This script can modify many files and paths recursively. ALWAYS backup first, perform a dry run, and never run in production. It surely goes without saying to measure thrice and cut once before running it against important locations, such as /var/www or production application directories, and unless you really know what you're doing absolutely avoid all system locations.

THIS SCRIPT IS PROVIDED ON AN "AS IS" BASIS WITHOUT ANY WARRANTIES OF ANY KIND. BY USING THIS SCRIPT, THE USER CONFIRMS THEY HAVE CONDUCTED THEIR OWN DUE DILIGENCE TO VERIFY ITS SUITABILITY AND SAFETY. THE USER VOLUNTARILY ACCEPTS FULL RISK ASSUMPTION FOR ANY DAMAGES OR DATA LOSS ARISING FROM ITS USE.

Requirements

• Bash
• find
• grep
• perl
• standard core utilities such as mv, dirname, and basename

Usage

janus-cli OLD NEW [ROOT]

Arguments:

• OLD: the literal string to search for. This must not be empty.
• NEW: the replacement string. This may be empty if you explicitly want to remove OLD.
• ROOT: the root directory to process. Defaults to the current directory.

If running directly from the repository checkout:

./janus oldtext newtext .

Environment options

Option	Default	Description
DRYRUN=1	off	Preview changes without modifying files or renaming paths.
RENAME_ROOT=1	off	Allow the root directory itself to be renamed if its basename contains OLD.
EXCLUDE_GIT=0	.git excluded	Include .git directories. By default, .git directories are skipped.

Examples

Preview changes under the current directory:

DRYRUN=1 ./janus oldtext newtext .

Apply changes under the current directory:

./janus oldtext newtext .

Preview a hostname change in Apache vhost files:

DRYRUN=1 ./janus old.example.com new.example.com /etc/apache2/sites-available

Apply a hostname change in Apache vhost files:

sudo ./janus old.example.com new.example.com /etc/apache2/sites-available

Preview a change under a webroot:

DRYRUN=1 ./janus old.example.com new.example.com /var/www

Allow the root directory itself to be renamed:

sudo RENAME_ROOT=1 ./janus old.example.com new.example.com /var/www/old.example.com

Include .git directories deliberately:

EXCLUDE_GIT=0 ./janus oldtext newtext .

Root rename behaviour

By default, janus-cli does not rename the root directory supplied as ROOT.

For example, this command processes content and child paths under /var/www/old.example.com, but does not rename /var/www/old.example.com itself:

./janus old.example.com new.example.com /var/www/old.example.com

To allow the root directory itself to be renamed, use:

RENAME_ROOT=1 ./janus old.example.com new.example.com /var/www/old.example.com

This default is intentional so the top-level target path does not unexpectedly disappear during a normal run.

.git handling

By default, .git directories are skipped. This helps avoid corrupting repository internals such as objects, refs, hooks, and metadata.

To include .git directories, set:

EXCLUDE_GIT=0

Line endings

The script should use Unix LF line endings. If it was edited on Windows and fails with an error similar to:

/usr/bin/env: 'bash\r': No such file or directory

convert it back to Unix line endings:

sed -i 's/\r$//' janus

or, if available:

dos2unix janus

Apache and Moodle notes

For an Apache and Moodle hostname change, janus-cli can help update filesystem-level references such as:

• Apache vhost config content
• Apache vhost filenames
• Moodle config.php
• webroot directory names
• hard-coded references in local project files

It does not update Moodle database content. After changing $CFG->wwwroot, use Moodle's supported search-and-replace tooling for database-stored URLs, then purge Moodle caches.

If an Apache vhost config file is renamed, the matching symlink in sites-enabled will not automatically follow the renamed file. Re-enable the site using the normal Apache tools, for example:

sudo a2dissite old.example.com.conf
sudo a2ensite new.example.com.conf
sudo apache2ctl configtest
sudo systemctl reload apache2

Recommended workflow

1. Back up the files and database involved.
2. Run with DRYRUN=1.
3. Review the planned content changes and renames.
4. Run without DRYRUN=1.
5. Run any application-specific follow-up tasks, such as Apache reloads or Moodle database URL replacement.
6. Search for remaining references to the old string.

Limitations

janus-cli performs literal string replacement in text files and path basenames. It does not understand application semantics, database contents, symlinks that point to renamed files, external service configuration, DNS, SSL certificates, cron jobs, or reverse proxy rules.

License

This script is licenced under the GNU Affero General Public License v3.0