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Cron: History, Overview & Cron expression

cron is a time-based job scheduler. A scheduled job is known as a cron job. Although typically used to automate system maintenance and administration it can be used to automate any task. cron is most suitable for scheduling repetitive tasks, as scheduling a one-time task can be accomplished via at.

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Cron topic overview

The analysis highlights History, Overview and Cron expression as prominent areas in the source structure around Cron.

Related topics
53
Source areas
3
Connected nodes
57
Extracted relationships
80
Concept neighborhoods
13
Bridge connections
57

What this topic covers Research coverage

Source areas are shown by the number of related topics found in each part of the analysis. Use smaller areas too: they can reveal specialized angles and content gaps.

History · 37 topics
Overview · 13 topics
Cron expression · 3 topics

Smaller areas are not necessarily less important. They contain fewer connections in this analysis and can be useful for finding specialized angles or coverage gaps.

Key facts & relationships

High-confidence facts extracted from structured source data. Use them as anchors for further research.

Developer
AT&T Bell Laboratories
Operating system
Unix and Unix-like, Plan 9, Inferno
Release
May 1975; 51 years ago (1975-05)
Type
Job scheduler
Written in
C

Explore all related topics Closing gaps

Browse the complete topic structure, not only the most central items. Less prominent entities and concepts can reveal missing angles, specialized context and useful research gaps. Each item opens a new analysis centered on that subject.

Overview

History

Cron expression

Advanced semantic analysis

Deeper signals for content research, entity SEO and topical coverage. The plain-language headings explain what each technical view is useful for.

How Cron connects Entity context

The extracted context around Cron shows recurring relationship patterns in the source. For example, Cron → Anacron, BSDs, GNU Project, In, ISC Cron, January, Linux, PAM, Paul Vixie, Red Hat, SELinux, The, Version, Vixie, With Another extracted example is Cron → ACM, An, August, Communications, Franta, In, Kurt Maly, MIPS, The, Though, Unix, Unix System, Unix-like. Use these groups to spot repeated connection types before inspecting the individual relationships.

Cron

Top relations

related to Modern versions · 15
Cron → Anacron, BSDs, GNU Project, In, ISC Cron, January, Linux, PAM, Paul Vixie, Red Hat, SELinux, The, Version, Vixie, With
related to Multi-user capability · 13
Cron → ACM, An, August, Communications, Franta, In, Kurt Maly, MIPS, The, Though, Unix, Unix System, Unix-like
related to Early versions · 6
Cron → Its, Read/usr/lib/crontabDetermine, Sleep, The, Unix, Version
related to External links · 6
Cron → ISC Cron, Shell, The Open GroupGNU, The Single UNIX Specification, Utilities Reference, Version
related to Standardization efforts · 5
Cron → In, OCPS, Open Cron Pattern Specification, The, Vixie
related to Nonstandard predefined scheduling definitions · 4
Cron → Debian, Since, Some, This
related to Time zone handling · 4
Cron → DST, Most, This, Thus
related to Non-standard characters · 3
Cron → Note, Quartz Java, The
related to overview · 3
Cron → Each, The, Users
see also · 3
Cron → LaunchdList, POSIX, Task Scheduler

Important terminology

Use these terms to understand the vocabulary surrounding the topic, not as a checklist for keyword stuffing.

Important terminology

time crontab daemon system job user run version file must users used task unix also scheduling files command event list

Cron relationships Subject–Predicate–Object triples

TTTA extracted 80 structured relationships around Cron. Examples in this analysis include Cron → Developer → AT&T Bell Laboratories and Cron → Operating system → Unix and Unix-like, Plan 9, Inferno. The table shows each extracted connection, where it came from and its confidence.

SubjectPredicateObjectConfidenceSrc
CronDeveloperAT&T Bell Laboratories1.00infobox
CronOperating systemUnix and Unix-like, Plan 9, Inferno1.00infobox
CronReleaseMay 1975; 51 years ago (1975-05)1.00infobox
CronTypeJob scheduler1.00infobox
CronWritten inC1.00infobox
Cronis atime-based job scheduler0.90text
Cronis amere pattern-matcher0.90text
first-weekdayinstance ofas well as supporting additional expression features0.80text
last-day-of-month.Nonstandard predefined scheduling definitionsSome cron implementations support the following non-standard macrosinstance ofas well as supporting additional expression features0.80text
PAMinstance ofadding features0.80text
SELinux supportinstance ofadding features0.80text
predefined schedulesinstance ofwith future versions planned to incrementally add features0.80text

Related concept clusters Concept neighborhoods

The concept neighborhoods around Cron bring nearby vocabulary together. In this analysis, examples include Version, Crontab and Job. Use the clusters to find adjacent concepts and terminology that may deserve separate research.

  • Cron
    • Version
    • Crontab
    • Job
    • Unix
    • System
    • Time
    • Use
    • Implementations
    • Files
    • File
    • Users
    • Daemon
  • cron
    • Version
    • Crontab
    • Job
    • Unix
    • System
    • Time
    • Use
    • Implementations
    • Files
    • File
    • Users
    • Daemon
  • job scheduler
    • Scheduling
    • Unix
    • Vixie
    • Also
    • Unix-like
    • Scheduled
    • Scheduler
    • Crontabs
    • Field
    • Crontab
    • Specification
    • File
  • unix system v
    • Unix
    • Users
    • Version
    • Unix-like
    • Etc
    • File
    • Crontab
    • User
    • Time
    • Scheduling
    • Daemon
    • Created
  • cron expression
    • Version
    • Crontab
    • Job
    • Unix
    • System
    • Time
    • Use
    • Implementations
    • Files
    • File
    • Users
    • Daemon
  • daemon
    • Files
    • Crontab
    • Jobs
    • Implementations
    • Run
    • Job
    • System
    • Unix-like
    • Scheduled
    • Crontabs
    • Etc
    • Systems
  • paul vixie
    • Job
    • Also
    • Jobs
    • Scheduled
    • Crontabs
    • Specification
    • Cron
    • Field
    • Queue
    • Scheduling
    • Files
    • Used
  • discrete event simulators
    • List
    • Place
    • Next
    • Queue
    • Time
    • Scheduled
    • Run
    • Execute
    • Future
    • Task
    • Purdue
    • Systems

Connections between topic areas Semantic bridges

For Cron, one of the stronger structural bridges in this analysis connects Cron with History. Bridges highlight paths between different parts of the map and can reveal research angles that are easy to miss in a flat list.

Min side: 3
Cron — History · splits 19 ⟂ 39
Cron — Overview · splits 44 ⟂ 14
Cron — Cron expression · splits 54 ⟂ 4

Map overview Semantic statistics

Cron

Nodes58
Edges57
Triples80
Avg. degree1.97
Density0.034483
Components1

Source & methodology

TTTA analyzes the structure around Cron to surface related topics, entities, relationships, concept neighborhoods and bridge connections. Use the map to explore areas such as History, Overview & Cron expression, including less central topics that may reveal useful research gaps. Automatically extracted connections are research leads rather than rewritten encyclopedia content.

Source: Wikipedia — Cron · EN edition · Analysis: TopicsToTalkAbout

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