response checker in a script
Clash Royale CLAN TAG#URR8PPP
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0
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I have following response checker in a script:
#!/bin/bash
test_fn()
WARNFILE=$1
echo
echo "--- BEGIN ---"
cat $WARNFILE
echo "--- END ---"
echo
while true; do
read -r -n 1 -p "Continue? [y/n]: " REPLY
case $REPLY in
[yY]) break ;;
[nNqQ]) echo;exit ;;
*) printf "33[31m%s33[0mn" " invalid input: $REPLY"
esac
done
test_fn /tmp/warning
it works fine...
$ ./test.sh
--- BEGIN ---
test warning
--- END ---
Continue? [y/n]: a invalid input: a
Continue? [y/n]: s invalid input: s
Continue? [y/n]: d invalid input: d
Continue? [y/n]: w invalid input: w
Continue? [y/n]: s invalid input: s
Continue? [y/n]: q
$
...until I change line:
test_fn /tmp/warning
with line:
test_fn /tmp/warning | tee -a /tmp/logfile
then, it scrambles lines:
$ ./test.sh
--- BEGIN ---
test warning
Continue? [y/n]: --- END ---
aContinue? [y/n]: invalid input: a
sContinue? [y/n]: invalid input: s
dContinue? [y/n]: invalid input: d
fContinue? [y/n]: invalid input: f
q
$
Anyone could please tell why it works so?
bash shell-script tee
edited Mar 24 at 13:19
Jeff Schaller
31.2k846105
asked Mar 24 at 12:55
DonJ
768
add a comment |Â
up vote
0
down vote
favorite
I have following response checker in a script:
#!/bin/bash
test_fn()
WARNFILE=$1
echo
echo "--- BEGIN ---"
cat $WARNFILE
echo "--- END ---"
echo
while true; do
read -r -n 1 -p "Continue? [y/n]: " REPLY
case $REPLY in
[yY]) break ;;
[nNqQ]) echo;exit ;;
*) printf "33[31m%s33[0mn" " invalid input: $REPLY"
esac
done
test_fn /tmp/warning
it works fine...
$ ./test.sh
--- BEGIN ---
test warning
--- END ---
Continue? [y/n]: a invalid input: a
Continue? [y/n]: s invalid input: s
Continue? [y/n]: d invalid input: d
Continue? [y/n]: w invalid input: w
Continue? [y/n]: s invalid input: s
Continue? [y/n]: q
$
...until I change line:
test_fn /tmp/warning
with line:
test_fn /tmp/warning | tee -a /tmp/logfile
then, it scrambles lines:
$ ./test.sh
--- BEGIN ---
test warning
Continue? [y/n]: --- END ---
aContinue? [y/n]: invalid input: a
sContinue? [y/n]: invalid input: s
dContinue? [y/n]: invalid input: d
fContinue? [y/n]: invalid input: f
q
$
Anyone could please tell why it works so?
bash shell-script tee
edited Mar 24 at 13:19
Jeff Schaller
31.2k846105
asked Mar 24 at 12:55
DonJ
768
4
It's becausereadis writing the prompt tostderrbut you are only redirectingstdouttoteeI think; that results in the originalstderrgetting intermixed with theteedstdout. Trytest_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
– steeldriver
Mar 24 at 13:29
@steeldriver, indeed, you are absolutely right, thank you.
– DonJ
Mar 24 at 17:42
add a comment |Â
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I have following response checker in a script:
#!/bin/bash
test_fn()
WARNFILE=$1
echo
echo "--- BEGIN ---"
cat $WARNFILE
echo "--- END ---"
echo
while true; do
read -r -n 1 -p "Continue? [y/n]: " REPLY
case $REPLY in
[yY]) break ;;
[nNqQ]) echo;exit ;;
*) printf "33[31m%s33[0mn" " invalid input: $REPLY"
esac
done
test_fn /tmp/warning
it works fine...
$ ./test.sh
--- BEGIN ---
test warning
--- END ---
Continue? [y/n]: a invalid input: a
Continue? [y/n]: s invalid input: s
Continue? [y/n]: d invalid input: d
Continue? [y/n]: w invalid input: w
Continue? [y/n]: s invalid input: s
Continue? [y/n]: q
$
...until I change line:
test_fn /tmp/warning
with line:
test_fn /tmp/warning | tee -a /tmp/logfile
then, it scrambles lines:
$ ./test.sh
--- BEGIN ---
test warning
Continue? [y/n]: --- END ---
aContinue? [y/n]: invalid input: a
sContinue? [y/n]: invalid input: s
dContinue? [y/n]: invalid input: d
fContinue? [y/n]: invalid input: f
q
$
Anyone could please tell why it works so?
bash shell-script tee
edited Mar 24 at 13:19
Jeff Schaller
31.2k846105
asked Mar 24 at 12:55
DonJ
768
I have following response checker in a script:
#!/bin/bash
test_fn()
WARNFILE=$1
echo
echo "--- BEGIN ---"
cat $WARNFILE
echo "--- END ---"
echo
while true; do
read -r -n 1 -p "Continue? [y/n]: " REPLY
case $REPLY in
[yY]) break ;;
[nNqQ]) echo;exit ;;
*) printf "33[31m%s33[0mn" " invalid input: $REPLY"
esac
done
test_fn /tmp/warning
it works fine...
$ ./test.sh
--- BEGIN ---
test warning
--- END ---
Continue? [y/n]: a invalid input: a
Continue? [y/n]: s invalid input: s
Continue? [y/n]: d invalid input: d
Continue? [y/n]: w invalid input: w
Continue? [y/n]: s invalid input: s
Continue? [y/n]: q
$
...until I change line:
test_fn /tmp/warning
with line:
test_fn /tmp/warning | tee -a /tmp/logfile
then, it scrambles lines:
$ ./test.sh
--- BEGIN ---
test warning
Continue? [y/n]: --- END ---
aContinue? [y/n]: invalid input: a
sContinue? [y/n]: invalid input: s
dContinue? [y/n]: invalid input: d
fContinue? [y/n]: invalid input: f
q
$
Anyone could please tell why it works so?
bash shell-script tee
edited Mar 24 at 13:19
Jeff Schaller
31.2k846105
asked Mar 24 at 12:55
DonJ
768
edited Mar 24 at 13:19
Jeff Schaller
31.2k846105
edited Mar 24 at 13:19
Jeff Schaller
31.2k846105
edited Mar 24 at 13:19
Jeff Schaller
31.2k846105
31.2k846105
asked Mar 24 at 12:55
DonJ
768
asked Mar 24 at 12:55
DonJ
768
asked Mar 24 at 12:55
DonJ
768
768
4
It's becausereadis writing the prompt tostderrbut you are only redirectingstdouttoteeI think; that results in the originalstderrgetting intermixed with theteedstdout. Trytest_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
– steeldriver
Mar 24 at 13:29
@steeldriver, indeed, you are absolutely right, thank you.
– DonJ
Mar 24 at 17:42
add a comment |Â
4
It's becausereadis writing the prompt tostderrbut you are only redirectingstdouttoteeI think; that results in the originalstderrgetting intermixed with theteedstdout. Trytest_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
– steeldriver
Mar 24 at 13:29
@steeldriver, indeed, you are absolutely right, thank you.
– DonJ
Mar 24 at 17:42
4
4
It's because
read is writing the prompt to stderr but you are only redirecting stdout to tee I think; that results in the original stderr getting intermixed with the teed stdout. Try test_fn /tmp/warning 2>&1 | tee -a /tmp/logfile– steeldriver
Mar 24 at 13:29
It's because
read is writing the prompt to stderr but you are only redirecting stdout to tee I think; that results in the original stderr getting intermixed with the teed stdout. Try test_fn /tmp/warning 2>&1 | tee -a /tmp/logfile– steeldriver
Mar 24 at 13:29
@steeldriver, indeed, you are absolutely right, thank you.
– DonJ
Mar 24 at 17:42
@steeldriver, indeed, you are absolutely right, thank you.
– DonJ
Mar 24 at 17:42
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
1
down vote
accepted
To convert a comment to an answer:
read -p writes the prompt to stderr; in order to get the results in-line for tee, pipe the function's stderr to stdout before the tee with:
test_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
To demonstrate read's behavior:
$ read -p "my prompt: " >/dev/null
my prompt: hi
$ read -p "my prompt: " 2>/dev/null
hi
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
To convert a comment to an answer:
read -p writes the prompt to stderr; in order to get the results in-line for tee, pipe the function's stderr to stdout before the tee with:
test_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
To demonstrate read's behavior:
$ read -p "my prompt: " >/dev/null
my prompt: hi
$ read -p "my prompt: " 2>/dev/null
hi
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
add a comment |Â
up vote
1
down vote
accepted
To convert a comment to an answer:
read -p writes the prompt to stderr; in order to get the results in-line for tee, pipe the function's stderr to stdout before the tee with:
test_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
To demonstrate read's behavior:
$ read -p "my prompt: " >/dev/null
my prompt: hi
$ read -p "my prompt: " 2>/dev/null
hi
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
add a comment |Â
up vote
1
down vote
accepted
up vote
1
down vote
accepted
To convert a comment to an answer:
read -p writes the prompt to stderr; in order to get the results in-line for tee, pipe the function's stderr to stdout before the tee with:
test_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
To demonstrate read's behavior:
$ read -p "my prompt: " >/dev/null
my prompt: hi
$ read -p "my prompt: " 2>/dev/null
hi
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
To convert a comment to an answer:
read -p writes the prompt to stderr; in order to get the results in-line for tee, pipe the function's stderr to stdout before the tee with:
test_fn /tmp/warning 2>&1 | tee -a /tmp/logfile
To demonstrate read's behavior:
$ read -p "my prompt: " >/dev/null
my prompt: hi
$ read -p "my prompt: " 2>/dev/null
hi
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
answered Mar 28 at 0:46
Jeff Schaller
31.2k846105
31.2k846105
add a comment |Â
add a comment |Â
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4
It's because
readis writing the prompt tostderrbut you are only redirectingstdouttoteeI think; that results in the originalstderrgetting intermixed with theteedstdout. Trytest_fn /tmp/warning 2>&1 | tee -a /tmp/logfile– steeldriver
Mar 24 at 13:29
@steeldriver, indeed, you are absolutely right, thank you.
– DonJ
Mar 24 at 17:42