Skip to Main Content
Unix in a Nutshell, 4th Edition
book

Unix in a Nutshell, 4th Edition

by Arnold Robbins
October 2005
Intermediate to advanced content levelIntermediate to advanced
908 pages
46h 42m
English
O'Reilly Media, Inc.
Content preview from Unix in a Nutshell, 4th Edition

Programmable Completion (Bash Only)

Bash and the readline library provide completion facilities, whereby you can type part of a command name, hit the TAB key, and have Bash fill in part or all of the rest of the command or filename. Programmable completion lets you, as a shell programmer, write code to customize the list of possible completions that Bash will present for a particular, partially entered word. This is accomplished through the combination of several facilities.

  • The complete command allows you provide a completion specification, or compspec, for individual commands. You specify, via various options, how to tailor the list of possible completions for the particular command. This is simple, but adequate for many needs. (See the complete entry in the section "Built-in Commands (Bash and Korn Shells),” later in this chapter.)

  • For more flexibility, you may use complete -F funcname command. This tells Bash to call funcname to provide the list of completions for command. You write the funcname function.

  • Within the code for a -F function, the COMP* shell variables provide information about the current command line. COMPREPLY is an array into which the function places the final list of completion results.

  • Also within the code for a -F function, you may use the compgen command to generate a list of results, such as “usernames that begin with a" or “all set variables.” The intent is that such results would be used with an array assignment:

    ...
    COMPREPLY=( $( compgen options arguments ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Learning the Unix Operating System, 5th Edition

Learning the Unix Operating System, 5th Edition

John Strang, Grace Todino, Jerry Peek
UNIX and Linux System Administration Handbook, 5th Edition

UNIX and Linux System Administration Handbook, 5th Edition

Trent R. Hein, Evi Nemeth, Garth Snyder, Ben Whaley, Dan Mackin

Publisher Resources

ISBN: 0596100299Errata Page