Issue with a for loop in bash script

[rmarkin]

Hello everyone,

I am borrowing the following bash script for use with my Mythbuntu system.

#!/bin/sh
REMOTE_NAME=DirectTV_RC16
for digit in $(echo $1 | sed -e 's/./& /g'); do
irsend --device=/dev/lircd1 SEND_ONCE $REMOTE_NAME $digit
sleep 0.4 # note, you may have to tweak the interdigit delay up a bit
done
irsend --device=/dev/lircd1 SEND_ONCE $REMOTE_NAME OK

When I pass a value to the script such as "select", it runs the irsend command once for each letter in the value "select" instead of substituting the entire value and only running the irsend command once. Any ideas how to fix this?

Thanks,
Robert

[rmarkin]

For instance, here is the output if I pass "one" to the above script.

robert@myth-dvr:~$ /usr/local/bin/change_channel.sh one
irsend: command failed: SEND_ONCE DirectTV_RC16 o
irsend: unknown command: "o"
irsend: command failed: SEND_ONCE DirectTV_RC16 n
irsend: unknown command: "n"
irsend: command failed: SEND_ONCE DirectTV_RC16 e
irsend: unknown command: "e"
robert@myth-dvr:~$

[burschik]

Hello everyone,

I am borrowing the following bash script for use with my Mythbuntu system.

#!/bin/sh
REMOTE_NAME=DirectTV_RC16
for digit in $(echo $1 | sed -e 's/./& /g'); do
irsend --device=/dev/lircd1 SEND_ONCE $REMOTE_NAME $digit
sleep 0.4 # note, you may have to tweak the interdigit delay up a bit
done
irsend --device=/dev/lircd1 SEND_ONCE $REMOTE_NAME OK

When I pass a value to the script such as "select", it runs the irsend command once for each letter in the value "select" instead of substituting the entire value and only running the irsend command once. Any ideas how to fix this?

Thanks,
Robert

If you don't know what this

sed -e 's/./& /g'

does, you had better read the sed manpage.

[rmarkin]

Thank you for the RTFM. I will read through it again in an attempt to understand it.

[rmarkin]

Well, I believe I actually understand less about the sed command now that I have read the manpage three times.

Can I infer from your post that the problem I am having is not related to the for loop and in fact is a problem with the sed command in the script? If so, is there some other way to achieve the same result?

[vsemaska]

I took that piece of code and put it into a script to see what happens. This is what I got:

# ./a.bash select
#!/bin/bash -vx

echo $1 | sed -e 's/./& /g'
+ echo select
+ sed -e 's/./& /g'
s e l e c t

So the sed command is placing spaces between each letter so that's why you're getting multiple runs instead of one.

Why not take out the sed command entirely:

for digit in $(echo $1); do