Last login: Thu 01 Oct 2026 on tty1
Archived edition.
$man 1 cat
Ten things the page says. Every one of them is on your machine right now — run the command above and check.
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01
With no FILE, or when FILE is -, read standard input.[man]
-
02
-v, --show-nonprinting
use ^ and M- notation, except for LFD and TAB.[man]
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03
-b, --number-nonblank
Number all nonempty output lines, starting with 1.[info]
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04
-s, --squeeze-blank
Suppress repeated adjacent blank lines; output just one empty line instead of several.[info]
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05
On systems like MS-DOS that distinguish between text and binary files, 'cat' normally reads and writes in binary mode.[info]
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06
Similarly, 'cat' writes in text mode if one of the options -bensAE is used or if standard output is a terminal.[info]
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07
An exit status of zero indicates success, and a nonzero value indicates failure.[info]
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08
Concatenate FILE(s) to standard output.[man]
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09
-E, --show-ends
display $ at end of each line.[man]
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10
--version
output version information and exit.[man]
$run --yourself
See what is really in a file
cat's real job is not printing files, it is showing you the bytes you cannot see. -A is the flag that ends most whitespace arguments.
These commands write files, so run them in a scratch directory:
$ mkdir -p ~/motd-lab && cd ~/motd-lab$ printf 'one\ttab\n\n\nthree blanks above\n' > odd.txt
$ cat odd.txt
$ cat -A odd.txt
$ cat -s -n odd.txtWHAT YOU SHOULD SEEPlain cat looks ordinary. cat -A exposes the tab as ^I and every line end as $. cat -s collapses the blank run and -n numbers what is left.
$quiz -n 5
Five questions, each one taking a term out of a line above. Ten points for each. Tap hear it to have a question read to you; answering plays the verdict.
QUESTION 1 OF 5
Which term completes this line from the page? “With no FILE, or when FILE is -, read _____ input.”
From point 1 above.
QUESTION 2 OF 5
Which term completes this line from the page? “Number all _____ output lines, starting with 1.”
From point 3 above.
QUESTION 3 OF 5
Which term completes this line from the page? “On systems like _____ that distinguish between text and binary files, 'cat' normally reads and writes in binary mode.”
From point 5 above.
QUESTION 4 OF 5
Which term completes this line from the page? “An exit status of zero _____ success, and a nonzero value indicates failure.”
From point 7 above.
QUESTION 5 OF 5
Which term completes this line from the page? “_____ $ at end of each line.”
From point 9 above.
Answer all five to bank your points.
$play --chapters 5
Five chapters, three voices. Tap one to jump — the player at the bottom of the screen follows.
$tee --everyone
Know someone with ten minutes and a terminal? Send them today's page. This is the card that appears when you post it:
$su - operator
The Operator has a dispatch on cat(1),
and he files them for subscribers only. It is free.
Join the club, or read about
the series.
MOTD is a weekday reading of one manual page already installed on your own
machine. Every statement is quoted from that page or from the GNU info
documentation beside it, and every edition names the command that shows you
the source.
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