How can I use a shell variable to copy an sed pattern?

up vote
0
down vote

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I have SED patterns:

[^a-zA-Z0-9]

/b./s/.*c.. ([^ ]*) .*/1/p

and so on.

I need to pass these to an echo command as variables.

At the moment, I define the $pattern variable like so:

$pattern="[^a-zA-Z0-9]"

and then pipe it to echo, like so:

echo "$OUTPUT" | sed "s/$pattern/g"

But the code is not passing the pattern, but a command and returns the error

=[^a-zA-Z0-9]: command not found

What's going wrong?

edited Dec 7 '17 at 17:27

ilkkachu

50.1k676138

asked Dec 7 '17 at 16:45

Michael Riordan

385

Does pattern='[^a-zA-Z0-9]' work better? You're not assigning a variable with $pattern=. Take a look at eval as an alternative too... I can make it into a proper answer if it works...
â€“Â Zip
Dec 7 '17 at 16:55

see also: unix.stackexchange.com/q/32907/117549
â€“Â Jeff Schaller
Dec 7 '17 at 17:00

[^a-zA-Z0-9] is a pattern but /b./s/.c.. ([^ ]) .*/1/p is a full sed script.
â€“Â StÃ©phane Chazelas
Dec 7 '17 at 17:18

1

Just a little insight on the error. With dollar sign bash expands it as if it were a variable and because there was nothing in $pattern at that point, bash saw this: =[^a-zA-Z0-9]. And what's the next step? Executing the command with that name, thus the error.
â€“Â PesaThe
Dec 7 '17 at 17:57

add a commentÂ |Â

up vote
0
down vote

favorite

I have SED patterns:

[^a-zA-Z0-9]

/b./s/.*c.. ([^ ]*) .*/1/p

and so on.

I need to pass these to an echo command as variables.

At the moment, I define the $pattern variable like so:

$pattern="[^a-zA-Z0-9]"

and then pipe it to echo, like so:

echo "$OUTPUT" | sed "s/$pattern/g"

But the code is not passing the pattern, but a command and returns the error

=[^a-zA-Z0-9]: command not found

What's going wrong?

edited Dec 7 '17 at 17:27

ilkkachu

50.1k676138

asked Dec 7 '17 at 16:45

Michael Riordan

385

Does pattern='[^a-zA-Z0-9]' work better? You're not assigning a variable with $pattern=. Take a look at eval as an alternative too... I can make it into a proper answer if it works...
â€“Â Zip
Dec 7 '17 at 16:55

see also: unix.stackexchange.com/q/32907/117549
â€“Â Jeff Schaller
Dec 7 '17 at 17:00

[^a-zA-Z0-9] is a pattern but /b./s/.c.. ([^ ]) .*/1/p is a full sed script.
â€“Â StÃ©phane Chazelas
Dec 7 '17 at 17:18

1

Just a little insight on the error. With dollar sign bash expands it as if it were a variable and because there was nothing in $pattern at that point, bash saw this: =[^a-zA-Z0-9]. And what's the next step? Executing the command with that name, thus the error.
â€“Â PesaThe
Dec 7 '17 at 17:57

add a commentÂ |Â

up vote
0
down vote

favorite

I have SED patterns:

[^a-zA-Z0-9]

/b./s/.*c.. ([^ ]*) .*/1/p

and so on.

I need to pass these to an echo command as variables.

At the moment, I define the $pattern variable like so:

$pattern="[^a-zA-Z0-9]"

and then pipe it to echo, like so:

echo "$OUTPUT" | sed "s/$pattern/g"

But the code is not passing the pattern, but a command and returns the error

=[^a-zA-Z0-9]: command not found

What's going wrong?

edited Dec 7 '17 at 17:27

ilkkachu

50.1k676138

asked Dec 7 '17 at 16:45

Michael Riordan

385

I have SED patterns:

[^a-zA-Z0-9]

/b./s/.*c.. ([^ ]*) .*/1/p

and so on.

I need to pass these to an echo command as variables.

At the moment, I define the $pattern variable like so:

$pattern="[^a-zA-Z0-9]"

and then pipe it to echo, like so:

echo "$OUTPUT" | sed "s/$pattern/g"

But the code is not passing the pattern, but a command and returns the error

=[^a-zA-Z0-9]: command not found

What's going wrong?

edited Dec 7 '17 at 17:27

ilkkachu

50.1k676138

asked Dec 7 '17 at 16:45

Michael Riordan

385

edited Dec 7 '17 at 17:27

ilkkachu

50.1k676138

edited Dec 7 '17 at 17:27

ilkkachu

50.1k676138

edited Dec 7 '17 at 17:27

ilkkachu

50.1k676138

asked Dec 7 '17 at 16:45

Michael Riordan

385

asked Dec 7 '17 at 16:45

Michael Riordan

385

asked Dec 7 '17 at 16:45

Michael Riordan

385

Does pattern='[^a-zA-Z0-9]' work better? You're not assigning a variable with $pattern=. Take a look at eval as an alternative too... I can make it into a proper answer if it works...
â€“Â Zip
Dec 7 '17 at 16:55

see also: unix.stackexchange.com/q/32907/117549
â€“Â Jeff Schaller
Dec 7 '17 at 17:00

[^a-zA-Z0-9] is a pattern but /b./s/.c.. ([^ ]) .*/1/p is a full sed script.
â€“Â StÃ©phane Chazelas
Dec 7 '17 at 17:18

1

Just a little insight on the error. With dollar sign bash expands it as if it were a variable and because there was nothing in $pattern at that point, bash saw this: =[^a-zA-Z0-9]. And what's the next step? Executing the command with that name, thus the error.
â€“Â PesaThe
Dec 7 '17 at 17:57

add a commentÂ |Â

Does pattern='[^a-zA-Z0-9]' work better? You're not assigning a variable with $pattern=. Take a look at eval as an alternative too... I can make it into a proper answer if it works...
â€“Â Zip
Dec 7 '17 at 16:55

see also: unix.stackexchange.com/q/32907/117549
â€“Â Jeff Schaller
Dec 7 '17 at 17:00

[^a-zA-Z0-9] is a pattern but /b./s/.c.. ([^ ]) .*/1/p is a full sed script.
â€“Â StÃ©phane Chazelas
Dec 7 '17 at 17:18

1

Just a little insight on the error. With dollar sign bash expands it as if it were a variable and because there was nothing in $pattern at that point, bash saw this: =[^a-zA-Z0-9]. And what's the next step? Executing the command with that name, thus the error.
â€“Â PesaThe
Dec 7 '17 at 17:57

Does pattern='[^a-zA-Z0-9]' work better? You're not assigning a variable with $pattern=. Take a look at eval as an alternative too... I can make it into a proper answer if it works...
â€“Â Zip
Dec 7 '17 at 16:55

see also: unix.stackexchange.com/q/32907/117549
â€“Â Jeff Schaller
Dec 7 '17 at 17:00

[^a-zA-Z0-9] is a pattern but /b./s/.c.. ([^ ]) .*/1/p is a full sed script.
â€“Â StÃ©phane Chazelas
Dec 7 '17 at 17:18

Just a little insight on the error. With dollar sign bash expands it as if it were a variable and because there was nothing in $pattern at that point, bash saw this: =[^a-zA-Z0-9]. And what's the next step? Executing the command with that name, thus the error.
â€“Â PesaThe
Dec 7 '17 at 17:57

add a commentÂ |Â

2 Answers
2

active

oldest

votes

up vote
2
down vote

$ pattern='[^a-zA-Z0-9]'
$ echo "123 ABC" | sed "s/$pattern/g"
sed: -e expression #1, char 16: unterminated `s' command
$ echo "123 ABC" | sed "s/$pattern//g"
123ABC
$ echo "123 ABC" | sed "s/$pattern/XYZ/g"
123XYZABC

And...

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:57

FaxMax

428219

add a commentÂ |Â

up vote
1
down vote

Replace

$pattern="[^a-zA-Z0-9]"

pattern="[^a-zA-Z0-9]"

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

add a commentÂ |Â

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
2
down vote

$ pattern='[^a-zA-Z0-9]'
$ echo "123 ABC" | sed "s/$pattern/g"
sed: -e expression #1, char 16: unterminated `s' command
$ echo "123 ABC" | sed "s/$pattern//g"
123ABC
$ echo "123 ABC" | sed "s/$pattern/XYZ/g"
123XYZABC

And...

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:57

FaxMax

428219

add a commentÂ |Â

up vote
2
down vote

$ pattern='[^a-zA-Z0-9]'
$ echo "123 ABC" | sed "s/$pattern/g"
sed: -e expression #1, char 16: unterminated `s' command
$ echo "123 ABC" | sed "s/$pattern//g"
123ABC
$ echo "123 ABC" | sed "s/$pattern/XYZ/g"
123XYZABC

And...

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:57

FaxMax

428219

add a commentÂ |Â

up vote
2
down vote

$ pattern='[^a-zA-Z0-9]'
$ echo "123 ABC" | sed "s/$pattern/g"
sed: -e expression #1, char 16: unterminated `s' command
$ echo "123 ABC" | sed "s/$pattern//g"
123ABC
$ echo "123 ABC" | sed "s/$pattern/XYZ/g"
123XYZABC

And...

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:57

FaxMax

428219

$ pattern='[^a-zA-Z0-9]'
$ echo "123 ABC" | sed "s/$pattern/g"
sed: -e expression #1, char 16: unterminated `s' command
$ echo "123 ABC" | sed "s/$pattern//g"
123ABC
$ echo "123 ABC" | sed "s/$pattern/XYZ/g"
123XYZABC

And...

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:57

FaxMax

428219

answered Dec 7 '17 at 16:57

FaxMax

428219

answered Dec 7 '17 at 16:57

FaxMax

428219

answered Dec 7 '17 at 16:57

FaxMax

428219

add a commentÂ |Â

up vote
1
down vote

Replace

$pattern="[^a-zA-Z0-9]"

pattern="[^a-zA-Z0-9]"

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

add a commentÂ |Â

up vote
1
down vote

Replace

$pattern="[^a-zA-Z0-9]"

pattern="[^a-zA-Z0-9]"

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

add a commentÂ |Â

up vote
1
down vote

Replace

$pattern="[^a-zA-Z0-9]"

pattern="[^a-zA-Z0-9]"

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

Replace

$pattern="[^a-zA-Z0-9]"

pattern="[^a-zA-Z0-9]"

Shell variables are assigned without a leading $.

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

answered Dec 7 '17 at 16:55

Patrick Mevzek

2,0381721

add a commentÂ |Â

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