Most of the time, we can use commands efficiently with the help of Linux’s automatic completion capability.

TAB Completion

Variable Tab

1

$HISTS    # press Tab key to auto-complete this command
img

before completing

img

after completing

Command Tab

1

ec    # press Tab key to auto-complete this command
img

before completing

img

after completing

File Tab

1

    # press Tab key to auto-complete this command
img

before completing

img

after completing

Possible Completions

Can we use Alt+Shift+? keys to print out possible completion options.

Variable Alt+Shift+?

1

$HISTS    # press Alternate and Shift and Question Mark keys to print the possible variables
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before printing possible variables

img

after printing possible variables

Command Alt+Shift+?

1

ec    # press Alternate and Shift and Question Mark keys to print the possible variables
img

before printing possible commands

img

after printing possible commands

File Alt+Shift+?

1

/bin/le    # press Alternate and Shift and Question Mark keys to print the possible variables
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before printing possible files

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after printing possible files

Specific Completion

We can also get the corresponding completion through a specific combination of keys.

File Alt+Shift+/

1

/bin/le    # press Alternate and Shift and Slash Sign keys to print the possible variables
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before completing a nearest filename

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after completing a nearest filename

Username Alt+Shift+~

1

ro    # press Alternate and Shift and Tilde Sign keys to print the possible variables
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before completing a nearest username

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after completing a nearest username

Variable Alt+Shift+$

1

$PA    # press Alternate and Shift and Dollar Sign keys to print the possible variables
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before completing a nearest variable

img

after completing a nearest variable

Hostname Alt+Shift+@

1

dongc    # press Alternate and Shift and At Sign keys to print the possible variables
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before completing a nearest hostname

img

after completing a nearest hostname

Command Alt+Shift+!

1

ec    # press Alternate and Shift and Exclamation Mark keys to print the possible variables
img

before completing a nearest hostname

img

after completing a nearest hostname

References 8.4.6 Letting Readline Type For You

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