Bash string while loop
up vote
-2
down vote
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Is there anyway to do while(string) just like what is in c
In c we have null terminator, but I'm not sure whether bash has it
while [ $string ] in bash will terminate when there is a space, which is not what I want, how do I detect whether it reaches the end of string or not?
bash shell
asked Nov 22 at 1:26
maple
13
add a comment |
up vote
-2
down vote
favorite
Is there anyway to do while(string) just like what is in c
In c we have null terminator, but I'm not sure whether bash has it
while [ $string ] in bash will terminate when there is a space, which is not what I want, how do I detect whether it reaches the end of string or not?
bash shell
asked Nov 22 at 1:26
maple
13
2
Welcome to StackOverflow! The answer to your question may very well be "Yes, there is a way". Please have a look at stackoverflow.com/help/how-to-ask for tips on improving this question. Meta-code, even, or working code in a language with which you're more familiar, will demonstrate how you're thinking a program should work, even if you don't know how to write it. If you can, try to make an MCVE, so that we can have some confidence we're actually working on the right problem.
– ghoti
Nov 22 at 1:33
That said, is this the kind of thing you're looking for?x="Hello"; for ((i=0; i<${#x}; i++)) { printf '> %sn' "${x:$i:1}"; }
– ghoti
Nov 22 at 1:37
add a comment |
up vote
-2
down vote
favorite
up vote
-2
down vote
favorite
Is there anyway to do while(string) just like what is in c
In c we have null terminator, but I'm not sure whether bash has it
while [ $string ] in bash will terminate when there is a space, which is not what I want, how do I detect whether it reaches the end of string or not?
bash shell
asked Nov 22 at 1:26
maple
13
Is there anyway to do while(string) just like what is in c
In c we have null terminator, but I'm not sure whether bash has it
while [ $string ] in bash will terminate when there is a space, which is not what I want, how do I detect whether it reaches the end of string or not?
bash shell
bash shell
asked Nov 22 at 1:26
maple
13
asked Nov 22 at 1:26
maple
13
asked Nov 22 at 1:26
maple
13
asked Nov 22 at 1:26
maple
13
asked Nov 22 at 1:26
maple
13
13
2
Welcome to StackOverflow! The answer to your question may very well be "Yes, there is a way". Please have a look at stackoverflow.com/help/how-to-ask for tips on improving this question. Meta-code, even, or working code in a language with which you're more familiar, will demonstrate how you're thinking a program should work, even if you don't know how to write it. If you can, try to make an MCVE, so that we can have some confidence we're actually working on the right problem.
– ghoti
Nov 22 at 1:33
That said, is this the kind of thing you're looking for?x="Hello"; for ((i=0; i<${#x}; i++)) { printf '> %sn' "${x:$i:1}"; }
– ghoti
Nov 22 at 1:37
add a comment |
2
Welcome to StackOverflow! The answer to your question may very well be "Yes, there is a way". Please have a look at stackoverflow.com/help/how-to-ask for tips on improving this question. Meta-code, even, or working code in a language with which you're more familiar, will demonstrate how you're thinking a program should work, even if you don't know how to write it. If you can, try to make an MCVE, so that we can have some confidence we're actually working on the right problem.
– ghoti
Nov 22 at 1:33
That said, is this the kind of thing you're looking for?x="Hello"; for ((i=0; i<${#x}; i++)) { printf '> %sn' "${x:$i:1}"; }
– ghoti
Nov 22 at 1:37
2
2
Welcome to StackOverflow! The answer to your question may very well be "Yes, there is a way". Please have a look at stackoverflow.com/help/how-to-ask for tips on improving this question. Meta-code, even, or working code in a language with which you're more familiar, will demonstrate how you're thinking a program should work, even if you don't know how to write it. If you can, try to make an MCVE, so that we can have some confidence we're actually working on the right problem.
– ghoti
Nov 22 at 1:33
Welcome to StackOverflow! The answer to your question may very well be "Yes, there is a way". Please have a look at stackoverflow.com/help/how-to-ask for tips on improving this question. Meta-code, even, or working code in a language with which you're more familiar, will demonstrate how you're thinking a program should work, even if you don't know how to write it. If you can, try to make an MCVE, so that we can have some confidence we're actually working on the right problem.
– ghoti
Nov 22 at 1:33
That said, is this the kind of thing you're looking for?
x="Hello"; for ((i=0; i<${#x}; i++)) { printf '> %sn' "${x:$i:1}"; }– ghoti
Nov 22 at 1:37
That said, is this the kind of thing you're looking for?
x="Hello"; for ((i=0; i<${#x}; i++)) { printf '> %sn' "${x:$i:1}"; }– ghoti
Nov 22 at 1:37
add a comment |
1 Answer
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I assume that the loop is removing part of the string and that it should stop when the string is empty. The way to do that in Bash is:
while [[ $string ]]
or (more explicitly)
while [[ -n $string ]]
For shells that don't have [[...]] the equivalent is
while [ "$string" ]
or
while [ -n "$string" ]
The quotes are necessary to prevent various problems, including incorrect termination when the string contains only characters from $IFS (including, normally, the space character). Use Shellcheck on shell code to detect many quoting problems, including the one in the question (SC2086: Double quote to prevent globbing and word splitting).
answered Nov 22 at 20:44
pjh
1,584611
add a comment |
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1 Answer
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1 Answer
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active
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up vote
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down vote
I assume that the loop is removing part of the string and that it should stop when the string is empty. The way to do that in Bash is:
while [[ $string ]]
or (more explicitly)
while [[ -n $string ]]
For shells that don't have [[...]] the equivalent is
while [ "$string" ]
or
while [ -n "$string" ]
The quotes are necessary to prevent various problems, including incorrect termination when the string contains only characters from $IFS (including, normally, the space character). Use Shellcheck on shell code to detect many quoting problems, including the one in the question (SC2086: Double quote to prevent globbing and word splitting).
answered Nov 22 at 20:44
pjh
1,584611
add a comment |
up vote
0
down vote
I assume that the loop is removing part of the string and that it should stop when the string is empty. The way to do that in Bash is:
while [[ $string ]]
or (more explicitly)
while [[ -n $string ]]
For shells that don't have [[...]] the equivalent is
while [ "$string" ]
or
while [ -n "$string" ]
The quotes are necessary to prevent various problems, including incorrect termination when the string contains only characters from $IFS (including, normally, the space character). Use Shellcheck on shell code to detect many quoting problems, including the one in the question (SC2086: Double quote to prevent globbing and word splitting).
answered Nov 22 at 20:44
pjh
1,584611
add a comment |
up vote
0
down vote
up vote
0
down vote
I assume that the loop is removing part of the string and that it should stop when the string is empty. The way to do that in Bash is:
while [[ $string ]]
or (more explicitly)
while [[ -n $string ]]
For shells that don't have [[...]] the equivalent is
while [ "$string" ]
or
while [ -n "$string" ]
The quotes are necessary to prevent various problems, including incorrect termination when the string contains only characters from $IFS (including, normally, the space character). Use Shellcheck on shell code to detect many quoting problems, including the one in the question (SC2086: Double quote to prevent globbing and word splitting).
answered Nov 22 at 20:44
pjh
1,584611
I assume that the loop is removing part of the string and that it should stop when the string is empty. The way to do that in Bash is:
while [[ $string ]]
or (more explicitly)
while [[ -n $string ]]
For shells that don't have [[...]] the equivalent is
while [ "$string" ]
or
while [ -n "$string" ]
The quotes are necessary to prevent various problems, including incorrect termination when the string contains only characters from $IFS (including, normally, the space character). Use Shellcheck on shell code to detect many quoting problems, including the one in the question (SC2086: Double quote to prevent globbing and word splitting).
answered Nov 22 at 20:44
pjh
1,584611
answered Nov 22 at 20:44
pjh
1,584611
answered Nov 22 at 20:44
pjh
1,584611
answered Nov 22 at 20:44
pjh
1,584611
1,584611
add a comment |
add a comment |
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Welcome to StackOverflow! The answer to your question may very well be "Yes, there is a way". Please have a look at stackoverflow.com/help/how-to-ask for tips on improving this question. Meta-code, even, or working code in a language with which you're more familiar, will demonstrate how you're thinking a program should work, even if you don't know how to write it. If you can, try to make an MCVE, so that we can have some confidence we're actually working on the right problem.
– ghoti
Nov 22 at 1:33
That said, is this the kind of thing you're looking for?
x="Hello"; for ((i=0; i<${#x}; i++)) { printf '> %sn' "${x:$i:1}"; }– ghoti
Nov 22 at 1:37