Glossary

Argument file — a file of inputs, named with :::: or --a, one input per line.

Cartesian product — what multiple input sources produce by default: every item of one list combined with every item of the others.

Citation notice — the upstream build's one-time request, printed to standard error, to cite the tool in published work. Settled by parallel --citation; the Debian and Ubuntu package never shows it.

Dry run — --dry-run: print the commands a run would execute, and execute none of them.

env_parallel — the companion program that lets jobs use your own shell's functions, aliases and environment.

Exitval — a job's exit value as recorded in the job log; 0 is success. The whole run's exit status is the count of jobs whose Exitval was not 0.

Input source — where a job list comes from: ::: arguments, :::: files, standard input, or a --pipe stream.

Job — one execution of the command template with one set of inputs.

Job log — the --joblog file: one tab-separated line per job with its sequence number, host, times, exit value and command.

Keep order — -k / --keep-order: print each job's output in input order rather than finish order.

Link — --link (or :::+): walk two input sources in step, pairing items, instead of combining them.

Replacement string — a placeholder in the command template filled from the input: {} {/} {//} {.} {/.}, and positional {1} {2} …

Results — --results DIR: save every job's output and error streams to per-job files under a directory.

Retry failed — --retry-failed: with a job log, run again only the jobs that failed.

Resume — --resume: with a job log, skip jobs already recorded and run the rest — for interrupted runs.

Sequence number — a job's position in the input list, starting at 1; seen as {#}, in job logs, and in --results bookkeeping.

Slot — one of the --jobs places a job can occupy; a job runs when a slot is free.

sshlogin — a host given with --sshlogin that takes a share of the jobs over SSH.