ANSI C quoting for tab and newline sometimes does not work
I am trying to use a newline in bash. I found that I need ANSI C quoting for that (i.e. $'n'), but this often does not work for me. So I am wondering what I am doing wrong.
# This works
>> echo $'anbnc'
a
b
c
# This doesn't
>> A=$'anbnc'
>> echo $A
a b c
# Also, this does not work
>> A="a b c"
>> echo ${A// /$'n'}
a b c
If I use tab instead of newline, I have the same problems. Other ANSI C quoting work like ', or ", or even b.
GNU Bash; version: 4.3.11(1)
bash escape-characters
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
add a comment |
I am trying to use a newline in bash. I found that I need ANSI C quoting for that (i.e. $'n'), but this often does not work for me. So I am wondering what I am doing wrong.
# This works
>> echo $'anbnc'
a
b
c
# This doesn't
>> A=$'anbnc'
>> echo $A
a b c
# Also, this does not work
>> A="a b c"
>> echo ${A// /$'n'}
a b c
If I use tab instead of newline, I have the same problems. Other ANSI C quoting work like ', or ", or even b.
GNU Bash; version: 4.3.11(1)
bash escape-characters
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
add a comment |
I am trying to use a newline in bash. I found that I need ANSI C quoting for that (i.e. $'n'), but this often does not work for me. So I am wondering what I am doing wrong.
# This works
>> echo $'anbnc'
a
b
c
# This doesn't
>> A=$'anbnc'
>> echo $A
a b c
# Also, this does not work
>> A="a b c"
>> echo ${A// /$'n'}
a b c
If I use tab instead of newline, I have the same problems. Other ANSI C quoting work like ', or ", or even b.
GNU Bash; version: 4.3.11(1)
bash escape-characters
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
I am trying to use a newline in bash. I found that I need ANSI C quoting for that (i.e. $'n'), but this often does not work for me. So I am wondering what I am doing wrong.
# This works
>> echo $'anbnc'
a
b
c
# This doesn't
>> A=$'anbnc'
>> echo $A
a b c
# Also, this does not work
>> A="a b c"
>> echo ${A// /$'n'}
a b c
If I use tab instead of newline, I have the same problems. Other ANSI C quoting work like ', or ", or even b.
GNU Bash; version: 4.3.11(1)
bash escape-characters
bash escape-characters
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
asked Dec 20 '18 at 19:18
Hielke Walinga
21027
21027
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Because you've not quoted the variable in:
echo $A
it is subject to splitting and globbing. The first step is the expansion of the variable's contents:
echo a $'n' b $'n' c -- where the $'n' bits represent actual newlines.
Then, the various pieces are split on $IFS, resulting in:
echo a b c
Then, since there are no wildcards to generate additional filenames, the strings are passed on to echo.
When you quote the variable, with echo "$A", you inhibit splitting and globbing.
See the change yourself if you modify IFS:
oIFS=$IFS
IFS=
echo $A
IFS=$oIFS
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
add a comment |
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1 Answer
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1 Answer
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active
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active
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Because you've not quoted the variable in:
echo $A
it is subject to splitting and globbing. The first step is the expansion of the variable's contents:
echo a $'n' b $'n' c -- where the $'n' bits represent actual newlines.
Then, the various pieces are split on $IFS, resulting in:
echo a b c
Then, since there are no wildcards to generate additional filenames, the strings are passed on to echo.
When you quote the variable, with echo "$A", you inhibit splitting and globbing.
See the change yourself if you modify IFS:
oIFS=$IFS
IFS=
echo $A
IFS=$oIFS
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
add a comment |
Because you've not quoted the variable in:
echo $A
it is subject to splitting and globbing. The first step is the expansion of the variable's contents:
echo a $'n' b $'n' c -- where the $'n' bits represent actual newlines.
Then, the various pieces are split on $IFS, resulting in:
echo a b c
Then, since there are no wildcards to generate additional filenames, the strings are passed on to echo.
When you quote the variable, with echo "$A", you inhibit splitting and globbing.
See the change yourself if you modify IFS:
oIFS=$IFS
IFS=
echo $A
IFS=$oIFS
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
add a comment |
Because you've not quoted the variable in:
echo $A
it is subject to splitting and globbing. The first step is the expansion of the variable's contents:
echo a $'n' b $'n' c -- where the $'n' bits represent actual newlines.
Then, the various pieces are split on $IFS, resulting in:
echo a b c
Then, since there are no wildcards to generate additional filenames, the strings are passed on to echo.
When you quote the variable, with echo "$A", you inhibit splitting and globbing.
See the change yourself if you modify IFS:
oIFS=$IFS
IFS=
echo $A
IFS=$oIFS
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
Because you've not quoted the variable in:
echo $A
it is subject to splitting and globbing. The first step is the expansion of the variable's contents:
echo a $'n' b $'n' c -- where the $'n' bits represent actual newlines.
Then, the various pieces are split on $IFS, resulting in:
echo a b c
Then, since there are no wildcards to generate additional filenames, the strings are passed on to echo.
When you quote the variable, with echo "$A", you inhibit splitting and globbing.
See the change yourself if you modify IFS:
oIFS=$IFS
IFS=
echo $A
IFS=$oIFS
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
answered Dec 20 '18 at 19:24
Jeff Schaller
38.8k1053125
38.8k1053125
add a comment |
add a comment |
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