Bash script capturing output to terminal

Question

I want to capture into my bash script (in a variable) the output of some command that prints its output to terminal. I have tried the following:

TEST_OUT=`the_command ARG1`   #Nope

#Putting the line "the_command ARG1" into a separate script, testing2.sh,

TEST_OUT=$(./testing2.sh)   #Nope

testing2.sh
TEST_OUT=$?  #Nope

I am 100% sure that when I run...

> the_command ARG1

...in a terminal, it prints to the terminal exactly the information I want to capture.

Thank you for any help!

Standard error output does not seem to be captured in your scripts so it will be printed to the terminal. — C2H5OH
– C2H5OH, Commented Aug 3, 2012 at 17:40
If the output is being sent to stderr, you'll need to redirect that to stdout before it can be capture in your var. Try TEST_OUT=$(the_command ARG1 2>&1) — Shawn Chin
– Shawn Chin, Commented Aug 3, 2012 at 17:42
Hey sorry, new to bash and scripting here... Are there 2 ways to print to terminal, stderr and stdout? — JDS
– JDS, Commented Aug 3, 2012 at 17:46
@ShawnChin Oh shit it worked! Nice! Post your answer and I'll accept that — JDS
– JDS, Commented Aug 3, 2012 at 17:49
posted. BTW, you generally print to terminal using stdout and only use stderr for error messages (so it doesn't get hidden when someone redirects the output to a file or var). For quick explanation of stdout and stderr, see en.wikipedia.org/wiki/…. — Shawn Chin
– Shawn Chin, Commented Aug 3, 2012 at 17:52

Shawn Chin · Accepted Answer · 2012-08-03 17:49:43Z

19

If the output is being sent to stderr, you'll need to redirect that to stdout before it can be capture in your var. Try:

TEST_OUT=$(the_command ARG1 2>&1)

answered Aug 3, 2012 at 17:49

Shawn Chin

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2 Comments

JDS Over a year ago

Awesome I didn't know about the difference b/w stderr and stdout. Good stuff.

chepner Over a year ago

If you want only stderr, use $(the_command ARG1 2>&1 >/dev/null).

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