This is how you should push a string in a command's stdin.

command <<< word

Don't do this: echo word | command Using a bash "here strings" and "here documents" look leeter than piping echo into the command. Also prevents subshell execution. Word is also expanded as usual.

By: adeverteuil

2012-02-29 03:14:54

command bash stdin

11 Alternatives + Submit Alt

send a circular

don't need echo :P
This is sample output - yours may be different.
20

wall <<< "Broadcast This"

ioggstream · 2010-12-29 11:07:46 51
send a circular
This is sample output - yours may be different.
18

echo "dear admin, please ban eribsskog" | wall

winky · 2010-12-27 09:45:23 9
I hate `echo X | Y`

apart from not being generalisable to all shells, `Y <<< X` seems nicer to me than `echo X | Y`, e.g. <<< lol cat; it reads easier, you type less, and it also looks cool
This is sample output - yours may be different.
15

base64 -d <<< aHR0cDovL3d3dy50d2l0dGVyc2hlZXAuY29tL3Jlc3VsdHMucGhwP3U9Y29tbWFuZGxpbmVmdQo=

stu · 2009-03-27 23:20:23 123
Function to split a string into an array

Show Sample Output
This is sample output - yours may be different.
```
read -a ARR <<<'world domination now!'; echo ${ARR[2]};
now!

IFS=":" read -a ARR <<<"$PATH"; echo ${ARR[2]};
/usr/local/bin
```
10

read -a ARR <<<'world domination now!'; echo ${ARR[2]};

unefunge · 2010-12-03 16:27:03 6
Using bash inline

There are two ways to use "here documents" with bash to fill stdin: The following example shows use with the "bc" command. a) Using a delimiter at the end of data: less-than less-than eeooff bc > k=1024 > m=k*k > g=k*m > g > eeooff 1073741824 b) using the "inline" verion with three less-than symbols: less-than less-than less-than "k=1024; m=k*k; g=k*m; g" bc 1073741824 One nice advantage of using the triple less-than version is that the command can easily be recalled from command line history and re-executed. PS: in this "description", I had to use the name "less-than" to represent the less-than symbol because the commandlinefu input text box seems to eat up the real less-than symbols. Odd. Show Sample Output
This is sample output - yours may be different.
```
$ # example 1: with the "bc" (basic calculator) command
$ <<<"k=1024; m=k*k; g=k*m; g" bc
1073741824

$ # example 2: with the "at" command
$ <<< "/home/mirror/cron_rsync_mandriva_updates" at now + 1 min
warning: commands will be executed using (in order) a) $SHELL b) login shell c) /bin/sh
job 66 at Sat Jun 20 11:33:00 2009


$ # example 3: calculating how long it takes for a signal across the Atlantic in fibre optic cable
$ # reference: https://en.wikipedia.org/wiki/Speed_of_light
$ # example 3, part 1: how fast does light travel in glass?
$ bc <<< "scale=4;  speedoflight=186282; speedoflight/1.5"    # light in glass travels at c / 1.5
124188.0000
$ # example 3, part 2: how many seconds for light to cross Atlantic in glass?
$ bc <<< "scale=4; ocean=3716; speedoflight=124188; ocean/speedoflight"
.0299
```
9

<<<"k=1024; m=k*k; g=k*m; g" bc

mpb · 2009-06-17 10:35:10 12

What Others Think

But they don't look any "leeter" if you don't put the string in quotes. :-/ There is nothing wrong with piping it in with an echo, I don't care what you smell.

deltaray · 655 weeks and 2 days ago

"lol" :)

adeverteuil · 655 weeks and 2 days ago

Be more "leet"! Use FreeBSD like me! :D

Sepero · 549 weeks and 1 day ago

seofox · 137 weeks and 2 days ago

seofox · 136 weeks and 6 days ago

seofox · 136 weeks and 3 days ago

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wandasuwari · 35 weeks and 3 days ago

yeneba6574 · 14 weeks and 1 day ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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