Expanding a variable containing an equals sign and curly braces
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I'm writing a script that uses rsync and excludes files based on certain settings. I end up with an exclude flag that has a format of --exclude=foo, bar, baz.
However, upon trying to expand it within the rsync command, I noticed the flag is escaped. From the bash debugger, I can see my command of rsync $excludes becomes rsync '--exclude=foo,bar,baz', rather than the expected rsync --exclude=foo,bar,baz. Doing some testing, I found that any string containing =, , or will get wrapped in single quotes when expanded. Short of using eval on a constructed string, is there a way around this?
bash variable
asked Jul 4 at 14:23
ollien
1045
 |Â
show 3 more comments
up vote
1
down vote
favorite
I'm writing a script that uses rsync and excludes files based on certain settings. I end up with an exclude flag that has a format of --exclude=foo, bar, baz.
However, upon trying to expand it within the rsync command, I noticed the flag is escaped. From the bash debugger, I can see my command of rsync $excludes becomes rsync '--exclude=foo,bar,baz', rather than the expected rsync --exclude=foo,bar,baz. Doing some testing, I found that any string containing =, , or will get wrapped in single quotes when expanded. Short of using eval on a constructed string, is there a way around this?
bash variable
asked Jul 4 at 14:23
ollien
1045
Do you really want it to expand to--exclude=foo,bar,bazor are you trying to have brace expansion expand it to:--exclude=foo --exclude=bar --exclude=baz?
– Jesse_b
Jul 4 at 14:35
The former is the goal.
– ollien
Jul 4 at 14:35
I also think that isn't the right syntax. Should be--exclude foo. I don't think rsync takes braces either though.
– Jesse_b
Jul 4 at 14:36
Using the equals sign is the correct syntax.
– ollien
Jul 4 at 14:36
From the man page,--exclude=PATTERN exclude files matching PATTERN
– ollien
Jul 4 at 14:38
 |Â
show 3 more comments
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I'm writing a script that uses rsync and excludes files based on certain settings. I end up with an exclude flag that has a format of --exclude=foo, bar, baz.
However, upon trying to expand it within the rsync command, I noticed the flag is escaped. From the bash debugger, I can see my command of rsync $excludes becomes rsync '--exclude=foo,bar,baz', rather than the expected rsync --exclude=foo,bar,baz. Doing some testing, I found that any string containing =, , or will get wrapped in single quotes when expanded. Short of using eval on a constructed string, is there a way around this?
bash variable
asked Jul 4 at 14:23
ollien
1045
I'm writing a script that uses rsync and excludes files based on certain settings. I end up with an exclude flag that has a format of --exclude=foo, bar, baz.
However, upon trying to expand it within the rsync command, I noticed the flag is escaped. From the bash debugger, I can see my command of rsync $excludes becomes rsync '--exclude=foo,bar,baz', rather than the expected rsync --exclude=foo,bar,baz. Doing some testing, I found that any string containing =, , or will get wrapped in single quotes when expanded. Short of using eval on a constructed string, is there a way around this?
bash variable
asked Jul 4 at 14:23
ollien
1045
asked Jul 4 at 14:23
ollien
1045
asked Jul 4 at 14:23
ollien
1045
asked Jul 4 at 14:23
ollien
1045
1045
Do you really want it to expand to--exclude=foo,bar,bazor are you trying to have brace expansion expand it to:--exclude=foo --exclude=bar --exclude=baz?
– Jesse_b
Jul 4 at 14:35
The former is the goal.
– ollien
Jul 4 at 14:35
I also think that isn't the right syntax. Should be--exclude foo. I don't think rsync takes braces either though.
– Jesse_b
Jul 4 at 14:36
Using the equals sign is the correct syntax.
– ollien
Jul 4 at 14:36
From the man page,--exclude=PATTERN exclude files matching PATTERN
– ollien
Jul 4 at 14:38
 |Â
show 3 more comments
Do you really want it to expand to--exclude=foo,bar,bazor are you trying to have brace expansion expand it to:--exclude=foo --exclude=bar --exclude=baz?
– Jesse_b
Jul 4 at 14:35
The former is the goal.
– ollien
Jul 4 at 14:35
I also think that isn't the right syntax. Should be--exclude foo. I don't think rsync takes braces either though.
– Jesse_b
Jul 4 at 14:36
Using the equals sign is the correct syntax.
– ollien
Jul 4 at 14:36
From the man page,--exclude=PATTERN exclude files matching PATTERN
– ollien
Jul 4 at 14:38
Do you really want it to expand to
--exclude=foo,bar,baz or are you trying to have brace expansion expand it to: --exclude=foo --exclude=bar --exclude=baz?– Jesse_b
Jul 4 at 14:35
Do you really want it to expand to
--exclude=foo,bar,baz or are you trying to have brace expansion expand it to: --exclude=foo --exclude=bar --exclude=baz?– Jesse_b
Jul 4 at 14:35
The former is the goal.
– ollien
Jul 4 at 14:35
The former is the goal.
– ollien
Jul 4 at 14:35
I also think that isn't the right syntax. Should be
--exclude foo. I don't think rsync takes braces either though.– Jesse_b
Jul 4 at 14:36
I also think that isn't the right syntax. Should be
--exclude foo. I don't think rsync takes braces either though.– Jesse_b
Jul 4 at 14:36
Using the equals sign is the correct syntax.
– ollien
Jul 4 at 14:36
Using the equals sign is the correct syntax.
– ollien
Jul 4 at 14:36
From the man page,
--exclude=PATTERN exclude files matching PATTERN– ollien
Jul 4 at 14:38
From the man page,
--exclude=PATTERN exclude files matching PATTERN– ollien
Jul 4 at 14:38
 |Â
show 3 more comments
2 Answers
2
active
oldest
votes
up vote
2
down vote
accepted
Brace expansion won't occur when quoted. You should also store arguments in an array rather than a variable (when possible).
I think the following should work for you:
excludes=( $(--exclude=foo,bar,baz) )
rsync "$excludes[@]"
answered Jul 4 at 14:46
Jesse_b
10.1k22658
This does not work. This expands torsync '--exclude=foo' '--exclude=bar' '--exclude=baz'
– ollien
Jul 4 at 15:03
@ollien: That is what you need.--exclude=foo,bar,bazwould be a syntax error to rsync
– Jesse_b
Jul 4 at 15:07
rsync does not recognize the flag when it is prepended by a single quote.
– ollien
Jul 4 at 15:09
The single quote doesn't actually go to rsync, it will be consumed by the shell
– Jesse_b
Jul 4 at 15:10
1
You definitely do not need theechoin there.excl=( --exclude=a,b,c )works inbash.
– Kusalananda
Jul 8 at 12:24
 |Â
show 1 more comment
up vote
1
down vote
From the bash debugger, ... any string containing =, , or will get wrapped in single quotes when expanded.
If you mean the xtrace output (set -x), it does indeed like to display arguments in single quotes when they contain special characters. The output is in a format that would be usable as input to the shell.
That doesn't mean the quotes are part of the string, though.
Compare:
$ echo abc def ghi
+ echo abc 'def ghi'
abc def ghi
$ echo abc 'def ghi'
+ echo abc ''''def ghi''''
abc 'def ghi'
Though as far as I can see, it doesn't bother to quote strings containing the equal sign.
answered Jul 4 at 17:25
ilkkachu
47.3k668130
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
accepted
Brace expansion won't occur when quoted. You should also store arguments in an array rather than a variable (when possible).
I think the following should work for you:
excludes=( $(--exclude=foo,bar,baz) )
rsync "$excludes[@]"
answered Jul 4 at 14:46
Jesse_b
10.1k22658
This does not work. This expands torsync '--exclude=foo' '--exclude=bar' '--exclude=baz'
– ollien
Jul 4 at 15:03
@ollien: That is what you need.--exclude=foo,bar,bazwould be a syntax error to rsync
– Jesse_b
Jul 4 at 15:07
rsync does not recognize the flag when it is prepended by a single quote.
– ollien
Jul 4 at 15:09
The single quote doesn't actually go to rsync, it will be consumed by the shell
– Jesse_b
Jul 4 at 15:10
1
You definitely do not need theechoin there.excl=( --exclude=a,b,c )works inbash.
– Kusalananda
Jul 8 at 12:24
 |Â
show 1 more comment
up vote
2
down vote
accepted
Brace expansion won't occur when quoted. You should also store arguments in an array rather than a variable (when possible).
I think the following should work for you:
excludes=( $(--exclude=foo,bar,baz) )
rsync "$excludes[@]"
answered Jul 4 at 14:46
Jesse_b
10.1k22658
This does not work. This expands torsync '--exclude=foo' '--exclude=bar' '--exclude=baz'
– ollien
Jul 4 at 15:03
@ollien: That is what you need.--exclude=foo,bar,bazwould be a syntax error to rsync
– Jesse_b
Jul 4 at 15:07
rsync does not recognize the flag when it is prepended by a single quote.
– ollien
Jul 4 at 15:09
The single quote doesn't actually go to rsync, it will be consumed by the shell
– Jesse_b
Jul 4 at 15:10
1
You definitely do not need theechoin there.excl=( --exclude=a,b,c )works inbash.
– Kusalananda
Jul 8 at 12:24
 |Â
show 1 more comment
up vote
2
down vote
accepted
up vote
2
down vote
accepted
Brace expansion won't occur when quoted. You should also store arguments in an array rather than a variable (when possible).
I think the following should work for you:
excludes=( $(--exclude=foo,bar,baz) )
rsync "$excludes[@]"
answered Jul 4 at 14:46
Jesse_b
10.1k22658
Brace expansion won't occur when quoted. You should also store arguments in an array rather than a variable (when possible).
I think the following should work for you:
excludes=( $(--exclude=foo,bar,baz) )
rsync "$excludes[@]"
answered Jul 4 at 14:46
Jesse_b
10.1k22658
edited Jul 8 at 13:33
answered Jul 4 at 14:46
Jesse_b
10.1k22658
answered Jul 4 at 14:46
Jesse_b
10.1k22658
answered Jul 4 at 14:46
Jesse_b
10.1k22658
10.1k22658
This does not work. This expands torsync '--exclude=foo' '--exclude=bar' '--exclude=baz'
– ollien
Jul 4 at 15:03
@ollien: That is what you need.--exclude=foo,bar,bazwould be a syntax error to rsync
– Jesse_b
Jul 4 at 15:07
rsync does not recognize the flag when it is prepended by a single quote.
– ollien
Jul 4 at 15:09
The single quote doesn't actually go to rsync, it will be consumed by the shell
– Jesse_b
Jul 4 at 15:10
1
You definitely do not need theechoin there.excl=( --exclude=a,b,c )works inbash.
– Kusalananda
Jul 8 at 12:24
 |Â
show 1 more comment
This does not work. This expands torsync '--exclude=foo' '--exclude=bar' '--exclude=baz'
– ollien
Jul 4 at 15:03
@ollien: That is what you need.--exclude=foo,bar,bazwould be a syntax error to rsync
– Jesse_b
Jul 4 at 15:07
rsync does not recognize the flag when it is prepended by a single quote.
– ollien
Jul 4 at 15:09
The single quote doesn't actually go to rsync, it will be consumed by the shell
– Jesse_b
Jul 4 at 15:10
1
You definitely do not need theechoin there.excl=( --exclude=a,b,c )works inbash.
– Kusalananda
Jul 8 at 12:24
This does not work. This expands to
rsync '--exclude=foo' '--exclude=bar' '--exclude=baz'– ollien
Jul 4 at 15:03
This does not work. This expands to
rsync '--exclude=foo' '--exclude=bar' '--exclude=baz'– ollien
Jul 4 at 15:03
@ollien: That is what you need.
--exclude=foo,bar,baz would be a syntax error to rsync– Jesse_b
Jul 4 at 15:07
@ollien: That is what you need.
--exclude=foo,bar,baz would be a syntax error to rsync– Jesse_b
Jul 4 at 15:07
rsync does not recognize the flag when it is prepended by a single quote.
– ollien
Jul 4 at 15:09
rsync does not recognize the flag when it is prepended by a single quote.
– ollien
Jul 4 at 15:09
The single quote doesn't actually go to rsync, it will be consumed by the shell
– Jesse_b
Jul 4 at 15:10
The single quote doesn't actually go to rsync, it will be consumed by the shell
– Jesse_b
Jul 4 at 15:10
1
1
You definitely do not need the
echo in there. excl=( --exclude=a,b,c ) works in bash.– Kusalananda
Jul 8 at 12:24
You definitely do not need the
echo in there. excl=( --exclude=a,b,c ) works in bash.– Kusalananda
Jul 8 at 12:24
 |Â
show 1 more comment
up vote
1
down vote
From the bash debugger, ... any string containing =, , or will get wrapped in single quotes when expanded.
If you mean the xtrace output (set -x), it does indeed like to display arguments in single quotes when they contain special characters. The output is in a format that would be usable as input to the shell.
That doesn't mean the quotes are part of the string, though.
Compare:
$ echo abc def ghi
+ echo abc 'def ghi'
abc def ghi
$ echo abc 'def ghi'
+ echo abc ''''def ghi''''
abc 'def ghi'
Though as far as I can see, it doesn't bother to quote strings containing the equal sign.
answered Jul 4 at 17:25
ilkkachu
47.3k668130
add a comment |Â
up vote
1
down vote
From the bash debugger, ... any string containing =, , or will get wrapped in single quotes when expanded.
If you mean the xtrace output (set -x), it does indeed like to display arguments in single quotes when they contain special characters. The output is in a format that would be usable as input to the shell.
That doesn't mean the quotes are part of the string, though.
Compare:
$ echo abc def ghi
+ echo abc 'def ghi'
abc def ghi
$ echo abc 'def ghi'
+ echo abc ''''def ghi''''
abc 'def ghi'
Though as far as I can see, it doesn't bother to quote strings containing the equal sign.
answered Jul 4 at 17:25
ilkkachu
47.3k668130
add a comment |Â
up vote
1
down vote
up vote
1
down vote
From the bash debugger, ... any string containing =, , or will get wrapped in single quotes when expanded.
If you mean the xtrace output (set -x), it does indeed like to display arguments in single quotes when they contain special characters. The output is in a format that would be usable as input to the shell.
That doesn't mean the quotes are part of the string, though.
Compare:
$ echo abc def ghi
+ echo abc 'def ghi'
abc def ghi
$ echo abc 'def ghi'
+ echo abc ''''def ghi''''
abc 'def ghi'
Though as far as I can see, it doesn't bother to quote strings containing the equal sign.
answered Jul 4 at 17:25
ilkkachu
47.3k668130
From the bash debugger, ... any string containing =, , or will get wrapped in single quotes when expanded.
If you mean the xtrace output (set -x), it does indeed like to display arguments in single quotes when they contain special characters. The output is in a format that would be usable as input to the shell.
That doesn't mean the quotes are part of the string, though.
Compare:
$ echo abc def ghi
+ echo abc 'def ghi'
abc def ghi
$ echo abc 'def ghi'
+ echo abc ''''def ghi''''
abc 'def ghi'
Though as far as I can see, it doesn't bother to quote strings containing the equal sign.
answered Jul 4 at 17:25
ilkkachu
47.3k668130
answered Jul 4 at 17:25
ilkkachu
47.3k668130
answered Jul 4 at 17:25
ilkkachu
47.3k668130
answered Jul 4 at 17:25
ilkkachu
47.3k668130
47.3k668130
add a comment |Â
add a comment |Â
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Do you really want it to expand to
--exclude=foo,bar,bazor are you trying to have brace expansion expand it to:--exclude=foo --exclude=bar --exclude=baz?– Jesse_b
Jul 4 at 14:35
The former is the goal.
– ollien
Jul 4 at 14:35
I also think that isn't the right syntax. Should be
--exclude foo. I don't think rsync takes braces either though.– Jesse_b
Jul 4 at 14:36
Using the equals sign is the correct syntax.
– ollien
Jul 4 at 14:36
From the man page,
--exclude=PATTERN exclude files matching PATTERN– ollien
Jul 4 at 14:38