How to replace a string when another string is found in a line?
1
I want to replace a string 'xy' with another string 'ab' when string 'ny' is found in a line of a unix file.
Sample text:
If we have xy today we can go to ny.
If we have xy tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
Output text should look like:-
If we have ab today we can go to ny.
If we have ab tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
linux text-processing sed grep
edited Dec 9 at 8:41
Sparhawk
9,27363991
asked Dec 9 at 5:36
satyaki
122
|
show 4 more comments
1
I want to replace a string 'xy' with another string 'ab' when string 'ny' is found in a line of a unix file.
Sample text:
If we have xy today we can go to ny.
If we have xy tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
Output text should look like:-
If we have ab today we can go to ny.
If we have ab tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
linux text-processing sed grep
edited Dec 9 at 8:41
Sparhawk
9,27363991
asked Dec 9 at 5:36
satyaki
122
2
What have you tried? This is very easy to do.
– Nasir Riley
Dec 9 at 5:40
@G-Man We don't have a sample of the file but if he just wants to replace a string on lines where anther appears then he can just usegrepto print the lines wherenyappears and then usesedto replacexywithab.
– Nasir Riley
Dec 9 at 5:58
ISTM that the question that that answers is a rather twisted interpretation of the question that the OP asked. The output would be a subset of the input file, with the desired changes made in those lines.
– G-Man
Dec 9 at 6:01
@G-man What it seems to you could also be entirely different than what is being asked because he hasn't provided a sample of the contents of the file or the expected output. Until we have that, all we can go on its what we think is wanted which is why I haven't posted an answer.
– Nasir Riley
Dec 9 at 6:05
satyaki: You have given an example for the question "I want to replace a string 'xy' with another string 'ab' in every line of a file." Since the string 'ny' is found in every line of your input, you aren't demonstrating what's supposed to happen with lines that don't contain it.
– G-Man
Dec 9 at 6:42
|
show 4 more comments
1
1
1
I want to replace a string 'xy' with another string 'ab' when string 'ny' is found in a line of a unix file.
Sample text:
If we have xy today we can go to ny.
If we have xy tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
Output text should look like:-
If we have ab today we can go to ny.
If we have ab tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
linux text-processing sed grep
edited Dec 9 at 8:41
Sparhawk
9,27363991
asked Dec 9 at 5:36
satyaki
122
I want to replace a string 'xy' with another string 'ab' when string 'ny' is found in a line of a unix file.
Sample text:
If we have xy today we can go to ny.
If we have xy tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
Output text should look like:-
If we have ab today we can go to ny.
If we have ab tomorrow we can go to ny tomorrow.
If we have mn now we can go to ny now.
linux text-processing sed grep
linux text-processing sed grep
edited Dec 9 at 8:41
Sparhawk
9,27363991
asked Dec 9 at 5:36
satyaki
122
edited Dec 9 at 8:41
Sparhawk
9,27363991
asked Dec 9 at 5:36
satyaki
122
edited Dec 9 at 8:41
Sparhawk
9,27363991
edited Dec 9 at 8:41
Sparhawk
9,27363991
edited Dec 9 at 8:41
Sparhawk
9,27363991
9,27363991
asked Dec 9 at 5:36
satyaki
122
asked Dec 9 at 5:36
satyaki
122
asked Dec 9 at 5:36
satyaki
122
122
2
What have you tried? This is very easy to do.
– Nasir Riley
Dec 9 at 5:40
@G-Man We don't have a sample of the file but if he just wants to replace a string on lines where anther appears then he can just usegrepto print the lines wherenyappears and then usesedto replacexywithab.
– Nasir Riley
Dec 9 at 5:58
ISTM that the question that that answers is a rather twisted interpretation of the question that the OP asked. The output would be a subset of the input file, with the desired changes made in those lines.
– G-Man
Dec 9 at 6:01
@G-man What it seems to you could also be entirely different than what is being asked because he hasn't provided a sample of the contents of the file or the expected output. Until we have that, all we can go on its what we think is wanted which is why I haven't posted an answer.
– Nasir Riley
Dec 9 at 6:05
satyaki: You have given an example for the question "I want to replace a string 'xy' with another string 'ab' in every line of a file." Since the string 'ny' is found in every line of your input, you aren't demonstrating what's supposed to happen with lines that don't contain it.
– G-Man
Dec 9 at 6:42
|
show 4 more comments
2
What have you tried? This is very easy to do.
– Nasir Riley
Dec 9 at 5:40
@G-Man We don't have a sample of the file but if he just wants to replace a string on lines where anther appears then he can just usegrepto print the lines wherenyappears and then usesedto replacexywithab.
– Nasir Riley
Dec 9 at 5:58
ISTM that the question that that answers is a rather twisted interpretation of the question that the OP asked. The output would be a subset of the input file, with the desired changes made in those lines.
– G-Man
Dec 9 at 6:01
@G-man What it seems to you could also be entirely different than what is being asked because he hasn't provided a sample of the contents of the file or the expected output. Until we have that, all we can go on its what we think is wanted which is why I haven't posted an answer.
– Nasir Riley
Dec 9 at 6:05
satyaki: You have given an example for the question "I want to replace a string 'xy' with another string 'ab' in every line of a file." Since the string 'ny' is found in every line of your input, you aren't demonstrating what's supposed to happen with lines that don't contain it.
– G-Man
Dec 9 at 6:42
2
2
What have you tried? This is very easy to do.
– Nasir Riley
Dec 9 at 5:40
What have you tried? This is very easy to do.
– Nasir Riley
Dec 9 at 5:40
@G-Man We don't have a sample of the file but if he just wants to replace a string on lines where anther appears then he can just use
grep to print the lines where ny appears and then use sed to replace xy with ab.– Nasir Riley
Dec 9 at 5:58
@G-Man We don't have a sample of the file but if he just wants to replace a string on lines where anther appears then he can just use
grep to print the lines where ny appears and then use sed to replace xy with ab.– Nasir Riley
Dec 9 at 5:58
ISTM that the question that that answers is a rather twisted interpretation of the question that the OP asked. The output would be a subset of the input file, with the desired changes made in those lines.
– G-Man
Dec 9 at 6:01
ISTM that the question that that answers is a rather twisted interpretation of the question that the OP asked. The output would be a subset of the input file, with the desired changes made in those lines.
– G-Man
Dec 9 at 6:01
@G-man What it seems to you could also be entirely different than what is being asked because he hasn't provided a sample of the contents of the file or the expected output. Until we have that, all we can go on its what we think is wanted which is why I haven't posted an answer.
– Nasir Riley
Dec 9 at 6:05
@G-man What it seems to you could also be entirely different than what is being asked because he hasn't provided a sample of the contents of the file or the expected output. Until we have that, all we can go on its what we think is wanted which is why I haven't posted an answer.
– Nasir Riley
Dec 9 at 6:05
satyaki: You have given an example for the question "I want to replace a string 'xy' with another string 'ab' in every line of a file." Since the string 'ny' is found in every line of your input, you aren't demonstrating what's supposed to happen with lines that don't contain it.
– G-Man
Dec 9 at 6:42
satyaki: You have given an example for the question "I want to replace a string 'xy' with another string 'ab' in every line of a file." Since the string 'ny' is found in every line of your input, you aren't demonstrating what's supposed to happen with lines that don't contain it.
– G-Man
Dec 9 at 6:42
|
show 4 more comments
2 Answers
2
active
oldest
votes
5
sed is probably the simplest approach:
sed '/ny/s/xy/ab/g' file
It contains two sub-commands: /ny/ searches for a pattern, and s/xy/ab/g does actual substitution. Notice that it will replace all occurrences of xy; if you want to replace only first of them in each line just remove final g.
answered Dec 9 at 6:34
jimmij
30.8k870105
Nice +1. Much simpler than awk.
– Sparhawk
Dec 9 at 6:38
2
Strictly speaking/ny/is not a command but the address for the followingscommand (this could also have been a line number or a range of lines between two regular expressions or numbers).
– Kusalananda
Dec 9 at 8:28
add a comment |
2
An answer in awk:
awk '/ny/ {gsub(/xy/,"ab")}; {print}' test.txt
Explanation
/ny/: only do the following commands when there isnyon the line.
gsub(/xy/,"ab"): substitute/xy/withab, only on those lines.
{print}: regardless of what line you are on, print the line.
answered Dec 9 at 5:49
Sparhawk
9,27363991
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
5
sed is probably the simplest approach:
sed '/ny/s/xy/ab/g' file
It contains two sub-commands: /ny/ searches for a pattern, and s/xy/ab/g does actual substitution. Notice that it will replace all occurrences of xy; if you want to replace only first of them in each line just remove final g.
answered Dec 9 at 6:34
jimmij
30.8k870105
Nice +1. Much simpler than awk.
– Sparhawk
Dec 9 at 6:38
2
Strictly speaking/ny/is not a command but the address for the followingscommand (this could also have been a line number or a range of lines between two regular expressions or numbers).
– Kusalananda
Dec 9 at 8:28
add a comment |
5
sed is probably the simplest approach:
sed '/ny/s/xy/ab/g' file
It contains two sub-commands: /ny/ searches for a pattern, and s/xy/ab/g does actual substitution. Notice that it will replace all occurrences of xy; if you want to replace only first of them in each line just remove final g.
answered Dec 9 at 6:34
jimmij
30.8k870105
Nice +1. Much simpler than awk.
– Sparhawk
Dec 9 at 6:38
2
Strictly speaking/ny/is not a command but the address for the followingscommand (this could also have been a line number or a range of lines between two regular expressions or numbers).
– Kusalananda
Dec 9 at 8:28
add a comment |
5
5
5
sed is probably the simplest approach:
sed '/ny/s/xy/ab/g' file
It contains two sub-commands: /ny/ searches for a pattern, and s/xy/ab/g does actual substitution. Notice that it will replace all occurrences of xy; if you want to replace only first of them in each line just remove final g.
answered Dec 9 at 6:34
jimmij
30.8k870105
sed is probably the simplest approach:
sed '/ny/s/xy/ab/g' file
It contains two sub-commands: /ny/ searches for a pattern, and s/xy/ab/g does actual substitution. Notice that it will replace all occurrences of xy; if you want to replace only first of them in each line just remove final g.
answered Dec 9 at 6:34
jimmij
30.8k870105
edited Dec 9 at 8:27
answered Dec 9 at 6:34
jimmij
30.8k870105
answered Dec 9 at 6:34
jimmij
30.8k870105
answered Dec 9 at 6:34
jimmij
30.8k870105
30.8k870105
Nice +1. Much simpler than awk.
– Sparhawk
Dec 9 at 6:38
2
Strictly speaking/ny/is not a command but the address for the followingscommand (this could also have been a line number or a range of lines between two regular expressions or numbers).
– Kusalananda
Dec 9 at 8:28
add a comment |
Nice +1. Much simpler than awk.
– Sparhawk
Dec 9 at 6:38
2
Strictly speaking/ny/is not a command but the address for the followingscommand (this could also have been a line number or a range of lines between two regular expressions or numbers).
– Kusalananda
Dec 9 at 8:28
Nice +1. Much simpler than awk.
– Sparhawk
Dec 9 at 6:38
Nice +1. Much simpler than awk.
– Sparhawk
Dec 9 at 6:38
2
2
Strictly speaking
/ny/ is not a command but the address for the following s command (this could also have been a line number or a range of lines between two regular expressions or numbers).– Kusalananda
Dec 9 at 8:28
Strictly speaking
/ny/ is not a command but the address for the following s command (this could also have been a line number or a range of lines between two regular expressions or numbers).– Kusalananda
Dec 9 at 8:28
add a comment |
2
An answer in awk:
awk '/ny/ {gsub(/xy/,"ab")}; {print}' test.txt
Explanation
/ny/: only do the following commands when there isnyon the line.
gsub(/xy/,"ab"): substitute/xy/withab, only on those lines.
{print}: regardless of what line you are on, print the line.
answered Dec 9 at 5:49
Sparhawk
9,27363991
add a comment |
2
An answer in awk:
awk '/ny/ {gsub(/xy/,"ab")}; {print}' test.txt
Explanation
/ny/: only do the following commands when there isnyon the line.
gsub(/xy/,"ab"): substitute/xy/withab, only on those lines.
{print}: regardless of what line you are on, print the line.
answered Dec 9 at 5:49
Sparhawk
9,27363991
add a comment |
2
2
2
An answer in awk:
awk '/ny/ {gsub(/xy/,"ab")}; {print}' test.txt
Explanation
/ny/: only do the following commands when there isnyon the line.
gsub(/xy/,"ab"): substitute/xy/withab, only on those lines.
{print}: regardless of what line you are on, print the line.
answered Dec 9 at 5:49
Sparhawk
9,27363991
An answer in awk:
awk '/ny/ {gsub(/xy/,"ab")}; {print}' test.txt
Explanation
/ny/: only do the following commands when there isnyon the line.
gsub(/xy/,"ab"): substitute/xy/withab, only on those lines.
{print}: regardless of what line you are on, print the line.
answered Dec 9 at 5:49
Sparhawk
9,27363991
answered Dec 9 at 5:49
Sparhawk
9,27363991
answered Dec 9 at 5:49
Sparhawk
9,27363991
answered Dec 9 at 5:49
Sparhawk
9,27363991
9,27363991
add a comment |
add a comment |
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2
What have you tried? This is very easy to do.
– Nasir Riley
Dec 9 at 5:40
@G-Man We don't have a sample of the file but if he just wants to replace a string on lines where anther appears then he can just use
grepto print the lines wherenyappears and then usesedto replacexywithab.– Nasir Riley
Dec 9 at 5:58
ISTM that the question that that answers is a rather twisted interpretation of the question that the OP asked. The output would be a subset of the input file, with the desired changes made in those lines.
– G-Man
Dec 9 at 6:01
@G-man What it seems to you could also be entirely different than what is being asked because he hasn't provided a sample of the contents of the file or the expected output. Until we have that, all we can go on its what we think is wanted which is why I haven't posted an answer.
– Nasir Riley
Dec 9 at 6:05
satyaki: You have given an example for the question "I want to replace a string 'xy' with another string 'ab' in every line of a file." Since the string 'ny' is found in every line of your input, you aren't demonstrating what's supposed to happen with lines that don't contain it.
– G-Man
Dec 9 at 6:42