Comparing strings

Question

I am having trouble comparing two strings. Even though they are identical when printed, my if statement returns false.

#!/bin/bash

string1="HDMI"
string2="PC Speaker"

hash=$(pacmd list-sinks | grep active)
echo $hash
trigger="active port: <analog-output-speaker>"
echo $trigger

if [ "$hash" == "$trigger" ]; then
   pacmd set-card-profile 0 output:hdmi-stereo+input:analog-stereo  
   echo $string1
else
   pacmd set-card-profile 0 output:analog-stereo+input:analog-stereo    
   echo $string2
fi

It produces the following output:

active port: <analog-output-speaker>
active port: <analog-output-speaker>
Welcome to PulseAudio! Use "help" for usage information.
>>> >>> PC Speaker

Anthon · Accepted Answer · 2015-03-14 13:49:08Z

3

Always quote variables

you say echo $hash but that strips leading and trailing whitespace and condenses all internal spaces. it does not show the content of the variable $hash

say instead echo "<$hash>" and you will see the leading whitespace.

It looks like pulse audio is using a tab before the word active. So put a tab at the start of the value in trigger and it will work.

edited Mar 14, 2015 at 13:49

Anthon

81.4k42 gold badges174 silver badges228 bronze badges

answered Mar 14, 2015 at 12:28

Jasen

3,91516 silver badges16 bronze badges

Add a comment |

Sepahrad Salour · Accepted Answer · 2015-03-14 12:47:49Z

1

If you add set -vx under #!/bin/bash and then run your script you will see:

[[ active port: <analog-output-speaker> == active port: <analog-output-speaker> ]]

And you can see the strings are not the same because first string has some spaces.

for removing whole string's spaces you can use: trim -d '[[:space:]]

for removing leading string's spaces you can use: sed -e 's/^[[:space:]]*//'

for removing trailing string's spaces you can use: sed -e 's/[[:space:]]*$//'

edited Mar 14, 2015 at 12:47

answered Mar 14, 2015 at 12:37

Sepahrad Salour

2,6794 gold badges23 silver badges28 bronze badges

Add a comment |

azzid · Accepted Answer · 2015-03-14 12:36:23Z

0

Non-printables troubling you.

Try this:

$ hash="   active port: <analog-output-speaker>%%%%%"   
$ echo $hash
active port: <analog-output-speaker>%%%%%
$ echo "<$hash>"
<   active port: <analog-output-speaker>%%%%%>
$ if [[ "$hash" =~ "active port" ]]; then echo matched; else echo no match; fi
matched
$ if [[ "$hash" =~ "non active port" ]]; then echo matched; else echo no match; fi
no match

answered Mar 14, 2015 at 12:36

azzid

1,0203 gold badges11 silver badges26 bronze badges

Add a comment |

Stack Exchange Network

Comparing strings

3 Answers 3

You must log in to answer this question.

Hot Network Questions

Comparing strings

3 Answers 3

You must log in to answer this question.

Related

Hot Network Questions