redirect command output into variable and standard output in ksh

Question

I have some shell command. I would like to write the output to the standard output and save it into variable as well. I'd like to solve it with one command. I have tried these things.

ls > $VAR          # redirects the output to file which name is stored in $VAR
ls | tee -a $VAR   # writes to standard output as well as in file which name is stored in $VAR
VAR=`ls`           # output into $VAR, but it is not sent to standard output
VAR=`ls`;echo $VAR # ok, it works but these are two commands

Any idea?

Just curious about the 1 line limitation. that makes me thing youre not the root of, of also a user of the system target. I can't figure out why do you have that limitation. Anyway i have posted you a "doyourself" answer. — m3nda
– m3nda, Commented Jan 21, 2015 at 6:58

Gary Barker · Accepted Answer · 2011-10-26 11:50:58Z

59

How about:

VAR=$(ls | tee /dev/tty)

answered Oct 26, 2011 at 11:50

Gary Barker

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3 Comments

glenn jackman Over a year ago

Depending on your OS, var=$(ls | tee /proc/$$/fd/1) might work too.

m3nda Over a year ago

Even if this is working perfectly, i post you an "do-it-yourself way" example. Im a Linux/bash noob, but i like learn those tips :D

rugk Over a year ago

Note that this (tee) only catches STDOUT output and that programs often do not color it (i.e. use VAR=$(ls --color | tee /dev/tty) to get coloured output).

S.W.Joerns · Accepted Answer · 2013-07-30 08:18:22Z

3

great answer from @Gary_Barker, but this isn't possible on all systems.

On our teamcity there isn't a char-console. And there is another little problem.

If I use

VAR=$(ls -1); echo $VAR

it isn't the same like ls -1

My solution works, if it doesn't matter, that the output comes from error pipe.

VAR=$(ls -1 | tee >&2)

answered Jul 30, 2013 at 8:18

S.W.Joerns

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2 Comments

hoss Over a year ago

Make sure to double quote the echo if the result is more than one line. VAR=$(ls -1); echo "$VAR". otherwise it gets squished into a single line

Prabhat Kumar Singh Over a year ago

@hoss can you explain why this happen ?

m3nda · Accepted Answer · 2015-01-21 08:03:30Z

As i understand, VAR=`ls`;echo $VAR is OK but you don't like because has 2 commands on it.

While @Gary-Barker is working, i have not check on all systems. If you got problem with tee or another, you can build your own ALWAYS.

I don't know if you know that, but a lot of the programs you can use on Linux are just a bunch of code using the small binarys on system. While this is true, there's no sense about use 1 or 2 commans, because the final execution is really a bunch of little ones.

So, if your real problem is that you can only write a single command in your target, you can write your own "app", by making a sh script in /sbin folder an leaving it without .sh extension (because these are excecuted with ./ or sh prefix and not by name)

I wrote that as example:

#!/bin/bash if [ $1 ] then VAR=$*; echo $VAR fi

For this example i have make the file /sbin/varrun. I've tried it with the folling commands with successful (normal) output:

varrun ls
varrun uname
varrun uname -a

Note that i've not used "quotes" on commands with spaces.

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