bash tty input drain (or flush?)
I am using bash and I am trying to drain the stdin up to a given char and start reading then. The input come from the tty given by my terminal emulator (xterm, *-terminal, etc...)
#!/bin/bash
typeset a=''
stty -echo
while :
do
echo -ne ""
while :; do read -r -n 1 a ; [[ "$a" = ":" ]] && break; done
read a ; echo "got a='$a'"
done
I then put this in a scratch buffer in my editor so I can cut it (mouse)
bad
bad
bad
bad
: good
bad
bad
bad
bad
: good
Then I run my t.sh script and doing mouse paste repeatedly I got this
TC$ ./t.sh
got a='good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
Is that expected?
Is there an way to ignore all input until a given char is found.
In a nutshell this simulate what happen on a stdin tty (ptys) when sending a query escape sequence to a terminal that reply back the answer on the stdin (as if typed on the keyboard) and the operator, at the same time, polute the input flow by for instance doing auto repeat on [enter]
The terminal do emit a header that we can scan to drain the input, but with bash it seems hard to do.
Any help welcome :)
bash input flush
asked Jan 20 at 12:00
PhiPhi
14512
add a comment |
I am using bash and I am trying to drain the stdin up to a given char and start reading then. The input come from the tty given by my terminal emulator (xterm, *-terminal, etc...)
#!/bin/bash
typeset a=''
stty -echo
while :
do
echo -ne ""
while :; do read -r -n 1 a ; [[ "$a" = ":" ]] && break; done
read a ; echo "got a='$a'"
done
I then put this in a scratch buffer in my editor so I can cut it (mouse)
bad
bad
bad
bad
: good
bad
bad
bad
bad
: good
Then I run my t.sh script and doing mouse paste repeatedly I got this
TC$ ./t.sh
got a='good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
Is that expected?
Is there an way to ignore all input until a given char is found.
In a nutshell this simulate what happen on a stdin tty (ptys) when sending a query escape sequence to a terminal that reply back the answer on the stdin (as if typed on the keyboard) and the operator, at the same time, polute the input flow by for instance doing auto repeat on [enter]
The terminal do emit a header that we can scan to drain the input, but with bash it seems hard to do.
Any help welcome :)
bash input flush
asked Jan 20 at 12:00
PhiPhi
14512
add a comment |
I am using bash and I am trying to drain the stdin up to a given char and start reading then. The input come from the tty given by my terminal emulator (xterm, *-terminal, etc...)
#!/bin/bash
typeset a=''
stty -echo
while :
do
echo -ne ""
while :; do read -r -n 1 a ; [[ "$a" = ":" ]] && break; done
read a ; echo "got a='$a'"
done
I then put this in a scratch buffer in my editor so I can cut it (mouse)
bad
bad
bad
bad
: good
bad
bad
bad
bad
: good
Then I run my t.sh script and doing mouse paste repeatedly I got this
TC$ ./t.sh
got a='good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
Is that expected?
Is there an way to ignore all input until a given char is found.
In a nutshell this simulate what happen on a stdin tty (ptys) when sending a query escape sequence to a terminal that reply back the answer on the stdin (as if typed on the keyboard) and the operator, at the same time, polute the input flow by for instance doing auto repeat on [enter]
The terminal do emit a header that we can scan to drain the input, but with bash it seems hard to do.
Any help welcome :)
bash input flush
asked Jan 20 at 12:00
PhiPhi
14512
I am using bash and I am trying to drain the stdin up to a given char and start reading then. The input come from the tty given by my terminal emulator (xterm, *-terminal, etc...)
#!/bin/bash
typeset a=''
stty -echo
while :
do
echo -ne ""
while :; do read -r -n 1 a ; [[ "$a" = ":" ]] && break; done
read a ; echo "got a='$a'"
done
I then put this in a scratch buffer in my editor so I can cut it (mouse)
bad
bad
bad
bad
: good
bad
bad
bad
bad
: good
Then I run my t.sh script and doing mouse paste repeatedly I got this
TC$ ./t.sh
got a='good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
got a=': good'
got a='bad'
got a='bad'
Is that expected?
Is there an way to ignore all input until a given char is found.
In a nutshell this simulate what happen on a stdin tty (ptys) when sending a query escape sequence to a terminal that reply back the answer on the stdin (as if typed on the keyboard) and the operator, at the same time, polute the input flow by for instance doing auto repeat on [enter]
The terminal do emit a header that we can scan to drain the input, but with bash it seems hard to do.
Any help welcome :)
bash input flush
bash input flush
asked Jan 20 at 12:00
PhiPhi
14512
asked Jan 20 at 12:00
PhiPhi
14512
asked Jan 20 at 12:00
PhiPhi
14512
asked Jan 20 at 12:00
PhiPhi
14512
asked Jan 20 at 12:00
PhiPhi
14512
14512
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
With @triplee suggestion
#!/bin/bash
typeset a=''
stty -echo
while :
do
read -d :
read a ; echo "got a='$a'"
done
scratchpad to cut/paste into t.sh running
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
Run
TC$ ./t.sh
got a='good'
got a='bad'
got a='good'
got a='bad'
got a='bad'
got a=': good good'
answered Jan 20 at 13:42
PhiPhi
14512
I can't repro this result. It's also not clear what it's supposed to demonstrate. Why do you have a separatereadwithout a-d :? Demo (with a tweak to avoid the endless loop): ideone.com/QVcTck
– tripleee
Jan 22 at 5:45
add a comment |
read -d ':' _ will read input until the first colon.
while read -d :
do
printf 'Preread: Got "%s"n' "$REPLY"
read -r a
printf 'In loop: Got "%s"n' "$a"
done <<_
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
_
Output:
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
Thanx for the -d, it simplify the test case, but still no joy, still got the bad input.
– Phi
Jan 20 at 13:36
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
With @triplee suggestion
#!/bin/bash
typeset a=''
stty -echo
while :
do
read -d :
read a ; echo "got a='$a'"
done
scratchpad to cut/paste into t.sh running
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
Run
TC$ ./t.sh
got a='good'
got a='bad'
got a='good'
got a='bad'
got a='bad'
got a=': good good'
answered Jan 20 at 13:42
PhiPhi
14512
I can't repro this result. It's also not clear what it's supposed to demonstrate. Why do you have a separatereadwithout a-d :? Demo (with a tweak to avoid the endless loop): ideone.com/QVcTck
– tripleee
Jan 22 at 5:45
add a comment |
With @triplee suggestion
#!/bin/bash
typeset a=''
stty -echo
while :
do
read -d :
read a ; echo "got a='$a'"
done
scratchpad to cut/paste into t.sh running
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
Run
TC$ ./t.sh
got a='good'
got a='bad'
got a='good'
got a='bad'
got a='bad'
got a=': good good'
answered Jan 20 at 13:42
PhiPhi
14512
I can't repro this result. It's also not clear what it's supposed to demonstrate. Why do you have a separatereadwithout a-d :? Demo (with a tweak to avoid the endless loop): ideone.com/QVcTck
– tripleee
Jan 22 at 5:45
add a comment |
With @triplee suggestion
#!/bin/bash
typeset a=''
stty -echo
while :
do
read -d :
read a ; echo "got a='$a'"
done
scratchpad to cut/paste into t.sh running
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
Run
TC$ ./t.sh
got a='good'
got a='bad'
got a='good'
got a='bad'
got a='bad'
got a=': good good'
answered Jan 20 at 13:42
PhiPhi
14512
With @triplee suggestion
#!/bin/bash
typeset a=''
stty -echo
while :
do
read -d :
read a ; echo "got a='$a'"
done
scratchpad to cut/paste into t.sh running
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
Run
TC$ ./t.sh
got a='good'
got a='bad'
got a='good'
got a='bad'
got a='bad'
got a=': good good'
answered Jan 20 at 13:42
PhiPhi
14512
edited Jan 20 at 13:48
answered Jan 20 at 13:42
PhiPhi
14512
answered Jan 20 at 13:42
PhiPhi
14512
answered Jan 20 at 13:42
PhiPhi
14512
14512
I can't repro this result. It's also not clear what it's supposed to demonstrate. Why do you have a separatereadwithout a-d :? Demo (with a tweak to avoid the endless loop): ideone.com/QVcTck
– tripleee
Jan 22 at 5:45
add a comment |
I can't repro this result. It's also not clear what it's supposed to demonstrate. Why do you have a separatereadwithout a-d :? Demo (with a tweak to avoid the endless loop): ideone.com/QVcTck
– tripleee
Jan 22 at 5:45
I can't repro this result. It's also not clear what it's supposed to demonstrate. Why do you have a separate
read without a -d :? Demo (with a tweak to avoid the endless loop): ideone.com/QVcTck– tripleee
Jan 22 at 5:45
I can't repro this result. It's also not clear what it's supposed to demonstrate. Why do you have a separate
read without a -d :? Demo (with a tweak to avoid the endless loop): ideone.com/QVcTck– tripleee
Jan 22 at 5:45
add a comment |
read -d ':' _ will read input until the first colon.
while read -d :
do
printf 'Preread: Got "%s"n' "$REPLY"
read -r a
printf 'In loop: Got "%s"n' "$a"
done <<_
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
_
Output:
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
Thanx for the -d, it simplify the test case, but still no joy, still got the bad input.
– Phi
Jan 20 at 13:36
add a comment |
read -d ':' _ will read input until the first colon.
while read -d :
do
printf 'Preread: Got "%s"n' "$REPLY"
read -r a
printf 'In loop: Got "%s"n' "$a"
done <<_
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
_
Output:
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
Thanx for the -d, it simplify the test case, but still no joy, still got the bad input.
– Phi
Jan 20 at 13:36
add a comment |
read -d ':' _ will read input until the first colon.
while read -d :
do
printf 'Preread: Got "%s"n' "$REPLY"
read -r a
printf 'In loop: Got "%s"n' "$a"
done <<_
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
_
Output:
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
read -d ':' _ will read input until the first colon.
while read -d :
do
printf 'Preread: Got "%s"n' "$REPLY"
read -r a
printf 'In loop: Got "%s"n' "$a"
done <<_
bad
bad
: good
bad
bad
: good
bad
bad
: good
bad
bad
: good
_
Output:
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
Preread: Got "bad
bad
"
In loop: Got "good"
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
edited Jan 22 at 5:48
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
answered Jan 20 at 12:04
tripleeetripleee
91.1k13129184
91.1k13129184
Thanx for the -d, it simplify the test case, but still no joy, still got the bad input.
– Phi
Jan 20 at 13:36
add a comment |
Thanx for the -d, it simplify the test case, but still no joy, still got the bad input.
– Phi
Jan 20 at 13:36
Thanx for the -d, it simplify the test case, but still no joy, still got the bad input.
– Phi
Jan 20 at 13:36
Thanx for the -d, it simplify the test case, but still no joy, still got the bad input.
– Phi
Jan 20 at 13:36
add a comment |
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