How to get the output of if condition on terminal

Question

I have this example and i want to get on screen both condition and good Code:

if [ `echo condition` ]; then echo good; fi

The output that i want to get:

condition
good

The output that i got:

good

As the command echo condition will be replaced with another command. The if statement must check the return code of the condition command.

I try it but it doesn't work: $ rc=$(echo good && exit 5) $ echo $rc good $ if [ $rc -eq 0 ]; then > echo here > fi -bash: [: good: integer expression expected — Bouraoui Al-Moez L.A, Jun 26 '20 at 09:21
Does this answer your question? [Command inside if statement of bash script](https://stackoverflow.com/questions/5276393/command-inside-if-statement-of-bash-script) — ceving, Jun 26 '20 at 14:41

MichalH · Accepted Answer · 2020-06-26T10:52:19.117

2

Simply store it in a variable:

cond=$(echo condition)
if [ "$cond" ] ; then
    echo "$cond"
    echo good
fi

edited Jun 26 '20 at 10:52

answered Jun 26 '20 at 09:55

MichalH

1,062
9
20

I found this solution https://stackoverflow.com/a/13343457/12953642 which works perfectly as the the solution you propose. – Bouraoui Al-Moez L.A Jun 26 '20 at 10:27

ceving · Answer 2 · 2020-06-26T09:52:13.607

0

Do not use backticks anymore nowadays.

Store the output of your sub shell in a variable:

if condition=$(echo condition); then
  echo "$condition"
  echo good
fi

If you want to return the exit value of the sub shell, you have to write a function:

get-condition-result()
{
  local condition
  local result
  if condition=$(echo condition); then
    result=$?
    echo "$condition"
    echo good
  else
    result=$?
  fi
  return "$result"
}

edited Jun 26 '20 at 09:52

answered Jun 26 '20 at 09:24

ceving

21,900
13
104
178

1

maybe add some link or rationale to "do not use backticks nowadays"? Sounds like interesting topic – Przemysław Czechowski Jun 26 '20 at 09:28
I want to check the condition on the return code of the command echo condition as it will be replaced with another command. In your case you are the if statement is testing on condition – Bouraoui Al-Moez L.A Jun 26 '20 at 09:40
1

@BouraouiAl-MoezL.A Maybe you should write it into your question. – ceving Jun 26 '20 at 09:42

score 0 · Answer 3 · answered Jun 26 '20 at 11:16

Solution found here: https://stackoverflow.com/a/13343457/12953642

You can run your command without any additional syntax. For example, the following checks the exit code of grep to determine whether the regular expression matches or not:

if echo condition
then
    echo "good"
fi
if echo "condition" && curl
then
    echo "good"
else
    echo "error in command"
fi

Output:

condition
good
condition
curl: try 'curl --help' or 'curl --manual' for more information
error in command

How to get the output of if condition on terminal

3 Answers3