parrot_run - run a program in the Parrot virtual file system


*parrot_run [parrot_options] program [program_options]*


parrot_run runs an application or a shell inside the Parrot virtual filesystem. Parrot redirects the application's system calls to remote storage systems. Parrot currently supports the following remote storage systems: HTTP, GROW, FTP, GridFTP, iRODS, HDFS, XRootd, Chirp. This list may vary depending on how Parrot was built. Run parrot -h to see exactly what support is available on your system.

Parrot works by trapping the application's system calls through the ptrace debugging interface. It does not require any special privileges to install or run, so it is useful to ordinary users that wish to access data across wide area networks. The ptrace debugging interface does have some cost, so applications may run slower, depending on how many I/O operations they perform.

For complete details with examples, see the Parrot User's Manual


  • --check-driver driver Check for the presence of a given driver (e.g. http, ftp, etc) and return success if it is currently enabled.
  • -a --chirp-auth Use this Chirp authentication method. May be invoked multiple times to indicate a preferred list, in order.
  • -b --block-size Set the I/O block size hint.
  • -c --status-file Print exit status information to file.
  • -C Enable data channel authentication in GridFTP.
  • -d --debug Enable debugging for this sub-system.
  • -D Disable small file optimizations.
  • --dynamic-mounts Enable the use of parot_mount in this session.
  • -F Enable file snapshot caching for all protocols.
  • -f Disable following symlinks.
  • -G --gid Fake this gid; Real gid stays the same.
  • -h Show this screen.
  • --helper Enable use of helper library.
  • -i --tickets Comma-delimited list of tickets to use for authentication.
  • -I --debug-level-irods Set the iRODS driver internal debug level.
  • -K Checksum files where available.
  • -k Do not checksum files.
  • -l --ld-path Path to to use.
  • -m --ftab-file Use this file as a mountlist.
  • -M --mount Mount (redirect) /foo to /bar.
  • -e --env-list Record the environment variables.
  • -n --name-list Record all the file names.
  • --no-set-foreground Disable changing the foreground process group of the session.
  • -N --hostname Pretend that this is my hostname.
  • -o --debug-file Write debugging output to this file. By default, debugging is sent to stderr (":stderr"). You may specify logs to be sent to stdout (":stdout") instead.
  • -O --debug-rotate-max Rotate debug files of this size.
  • -p --proxy Use this proxy server for HTTP requests.
  • -Q Inhibit catalog queries to list /chirp.
  • -r --cvmfs-repos CVMFS repositories to enable (PARROT_CVMFS_REPO).
  • --cvmfs-repo-switching Allow repository switching with CVMFS.
  • -R --root-checksum Enforce this root filesystem checksum, where available.
  • -s Use streaming protocols without caching.
  • -S Enable whole session caching for all protocols.
  • --syscall-disable-debug Disable tracee access to the Parrot debug syscall.
  • -t --tempdir Where to store temporary files.
  • -T --timeout Maximum amount of time to retry failures. time)Maximum amount of time to retry failures.
  • --time-stop Stop virtual time at midnight, Jan 1st, 2001 UTC.
  • --time-warp Warp virtual time starting from midnight, Jan 1st, 2001 UTC.
  • -U --uid Fake this unix uid; Real uid stays the same.
  • -u --username Use this extended username.
  • --fake-setuid Track changes from setuid and setgid.
  • --valgrind Enable valgrind support for Parrot.
  • -v Display version number.
  • --is-running Test is Parrot is already running.
  • -w --work-dir Initial working directory.
  • -W Display table of system calls trapped.
  • -Y Force synchronous disk writes.
  • -Z Enable automatic decompression on .gz files.
  • --disable-service service Disable a compiled-in service (e.g. http, cvmfs, etc.)


parrot_run sets the environment variable PARROT_ENABLED to the value 1 for its child processes. This makes it possible to set a visible flag in your shell prompt when parrot_run is enabled.


parrot_run returns the exit status of the process that it runs. If parrot_run is unable to start the process, it will return non-zero.


To access a single remote file using vi:

% parrot_run vi /anonftp/

You can also run an entire shell inside of Parrot, like this:

% parrot_run bash
% cd /anonftp/
% ls -la
% cat README
% exit

To see the list of available Chirp servers around the world:

% parrot_run ls -la /chirp

Parrot can record the names of all the accessed files and the environment variables during the execution process of one program, like this:

% parrot_run --name-list list.txt --env-list envlist ls ~
The environment variables at the starting moment of your program will be recorded into envlist. The absolute paths of all the accessed files, together with the system call types, will be recorded into list.txt. For example, the file /usr/bin/ls is accessed using the stat system call, like this:
% /usr/bin/ls|stat


Docker by default blocks ptrace, the system call on which parrot relies. To run parrot inside docker, the container needs to be started using the --security-opt seccomp=unconfined command line argument. For example:

    docker run --security-opt seccomp=unconfined MY-DOCKER-IMAGE

The Cooperative Computing Tools are Copyright (C) 2005-2019 The University of Notre Dame. This software is distributed under the GNU General Public License. See the file COPYING for details.


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