how to remove first N-1 lines up to a given input string
I'm trying to remove the first N-1 lines up to the first match of a specified string
I am very new to scripting, but from my googling I believe I have the two commands I need, but don't know how to use them together:
grep -n -m 1 'STRING' file.txt |sed 's/([0-9]*).*/1/'
will give me the line N
sed -e '1,Nd' file.txt > file2.txt
will remove the first N lines from file.txt and place them in file2.txt
am I able to use '1,N-1d'?
Further, how can I get all of the above into one line, as I am executing this from ANSYS and it doesn't carry parameters from line to line
any help would be greatly appreciated
Thank you!
grep sed
edited Jan 3 at 15:50
George Udosen
20.6k94467
asked Jan 3 at 15:46
tricha122tricha122
111
add a comment |
I'm trying to remove the first N-1 lines up to the first match of a specified string
I am very new to scripting, but from my googling I believe I have the two commands I need, but don't know how to use them together:
grep -n -m 1 'STRING' file.txt |sed 's/([0-9]*).*/1/'
will give me the line N
sed -e '1,Nd' file.txt > file2.txt
will remove the first N lines from file.txt and place them in file2.txt
am I able to use '1,N-1d'?
Further, how can I get all of the above into one line, as I am executing this from ANSYS and it doesn't carry parameters from line to line
any help would be greatly appreciated
Thank you!
grep sed
edited Jan 3 at 15:50
George Udosen
20.6k94467
asked Jan 3 at 15:46
tricha122tricha122
111
add a comment |
I'm trying to remove the first N-1 lines up to the first match of a specified string
I am very new to scripting, but from my googling I believe I have the two commands I need, but don't know how to use them together:
grep -n -m 1 'STRING' file.txt |sed 's/([0-9]*).*/1/'
will give me the line N
sed -e '1,Nd' file.txt > file2.txt
will remove the first N lines from file.txt and place them in file2.txt
am I able to use '1,N-1d'?
Further, how can I get all of the above into one line, as I am executing this from ANSYS and it doesn't carry parameters from line to line
any help would be greatly appreciated
Thank you!
grep sed
edited Jan 3 at 15:50
George Udosen
20.6k94467
asked Jan 3 at 15:46
tricha122tricha122
111
I'm trying to remove the first N-1 lines up to the first match of a specified string
I am very new to scripting, but from my googling I believe I have the two commands I need, but don't know how to use them together:
grep -n -m 1 'STRING' file.txt |sed 's/([0-9]*).*/1/'
will give me the line N
sed -e '1,Nd' file.txt > file2.txt
will remove the first N lines from file.txt and place them in file2.txt
am I able to use '1,N-1d'?
Further, how can I get all of the above into one line, as I am executing this from ANSYS and it doesn't carry parameters from line to line
any help would be greatly appreciated
Thank you!
grep sed
grep sed
edited Jan 3 at 15:50
George Udosen
20.6k94467
asked Jan 3 at 15:46
tricha122tricha122
111
edited Jan 3 at 15:50
George Udosen
20.6k94467
asked Jan 3 at 15:46
tricha122tricha122
111
edited Jan 3 at 15:50
George Udosen
20.6k94467
edited Jan 3 at 15:50
George Udosen
20.6k94467
edited Jan 3 at 15:50
George Udosen
20.6k94467
20.6k94467
asked Jan 3 at 15:46
tricha122tricha122
111
asked Jan 3 at 15:46
tricha122tricha122
111
asked Jan 3 at 15:46
tricha122tricha122
111
111
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
Sure you can use grep and sed and bash arithmetic expansion, e.g.:
N=$(grep -n -m1 'STRING' file1.txt | cut -d: -f1)
sed "1,$(( N - 1 ))d" file1.txt > file2.txt
You can get the same effect with sed, e.g.:
sed '/STRING/!d; :a; n; ba' file1.txt > file2.txt
answered Jan 3 at 16:14
ThorThor
2,5231620
add a comment |
You could use awk (both the default mawk and the GNU gawk version work for this) to filter your file with a single command:
awk '/STRING/{y=1} y' file1.txt > file2.txt
Here, /STRING/{y=1} scans each input line for the regular expression pattern STRING and if it matches, set a variable y to 1. Both the name and value are chosen arbitrarily here, we just use this as a boolean flag to remember if we have seen the pattern you search already or not.
Then, also for each line, after performing the first check for that line, it evaluates the expression y. If it's a truthy value (like e.g. 1 here; while the variable being not defined yet or if it were 0 that would be falsey), awk performs the default action for that line, because we didn't specify any after the expression, which is to simply print that line.
That way, the variable gets set when our STRING pattern matches for the first time, and all lines after that, including the matched line itself get printed, those before that not.
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
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
Sure you can use grep and sed and bash arithmetic expansion, e.g.:
N=$(grep -n -m1 'STRING' file1.txt | cut -d: -f1)
sed "1,$(( N - 1 ))d" file1.txt > file2.txt
You can get the same effect with sed, e.g.:
sed '/STRING/!d; :a; n; ba' file1.txt > file2.txt
answered Jan 3 at 16:14
ThorThor
2,5231620
add a comment |
Sure you can use grep and sed and bash arithmetic expansion, e.g.:
N=$(grep -n -m1 'STRING' file1.txt | cut -d: -f1)
sed "1,$(( N - 1 ))d" file1.txt > file2.txt
You can get the same effect with sed, e.g.:
sed '/STRING/!d; :a; n; ba' file1.txt > file2.txt
answered Jan 3 at 16:14
ThorThor
2,5231620
add a comment |
Sure you can use grep and sed and bash arithmetic expansion, e.g.:
N=$(grep -n -m1 'STRING' file1.txt | cut -d: -f1)
sed "1,$(( N - 1 ))d" file1.txt > file2.txt
You can get the same effect with sed, e.g.:
sed '/STRING/!d; :a; n; ba' file1.txt > file2.txt
answered Jan 3 at 16:14
ThorThor
2,5231620
Sure you can use grep and sed and bash arithmetic expansion, e.g.:
N=$(grep -n -m1 'STRING' file1.txt | cut -d: -f1)
sed "1,$(( N - 1 ))d" file1.txt > file2.txt
You can get the same effect with sed, e.g.:
sed '/STRING/!d; :a; n; ba' file1.txt > file2.txt
answered Jan 3 at 16:14
ThorThor
2,5231620
answered Jan 3 at 16:14
ThorThor
2,5231620
answered Jan 3 at 16:14
ThorThor
2,5231620
answered Jan 3 at 16:14
ThorThor
2,5231620
2,5231620
add a comment |
add a comment |
You could use awk (both the default mawk and the GNU gawk version work for this) to filter your file with a single command:
awk '/STRING/{y=1} y' file1.txt > file2.txt
Here, /STRING/{y=1} scans each input line for the regular expression pattern STRING and if it matches, set a variable y to 1. Both the name and value are chosen arbitrarily here, we just use this as a boolean flag to remember if we have seen the pattern you search already or not.
Then, also for each line, after performing the first check for that line, it evaluates the expression y. If it's a truthy value (like e.g. 1 here; while the variable being not defined yet or if it were 0 that would be falsey), awk performs the default action for that line, because we didn't specify any after the expression, which is to simply print that line.
That way, the variable gets set when our STRING pattern matches for the first time, and all lines after that, including the matched line itself get printed, those before that not.
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
add a comment |
You could use awk (both the default mawk and the GNU gawk version work for this) to filter your file with a single command:
awk '/STRING/{y=1} y' file1.txt > file2.txt
Here, /STRING/{y=1} scans each input line for the regular expression pattern STRING and if it matches, set a variable y to 1. Both the name and value are chosen arbitrarily here, we just use this as a boolean flag to remember if we have seen the pattern you search already or not.
Then, also for each line, after performing the first check for that line, it evaluates the expression y. If it's a truthy value (like e.g. 1 here; while the variable being not defined yet or if it were 0 that would be falsey), awk performs the default action for that line, because we didn't specify any after the expression, which is to simply print that line.
That way, the variable gets set when our STRING pattern matches for the first time, and all lines after that, including the matched line itself get printed, those before that not.
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
add a comment |
You could use awk (both the default mawk and the GNU gawk version work for this) to filter your file with a single command:
awk '/STRING/{y=1} y' file1.txt > file2.txt
Here, /STRING/{y=1} scans each input line for the regular expression pattern STRING and if it matches, set a variable y to 1. Both the name and value are chosen arbitrarily here, we just use this as a boolean flag to remember if we have seen the pattern you search already or not.
Then, also for each line, after performing the first check for that line, it evaluates the expression y. If it's a truthy value (like e.g. 1 here; while the variable being not defined yet or if it were 0 that would be falsey), awk performs the default action for that line, because we didn't specify any after the expression, which is to simply print that line.
That way, the variable gets set when our STRING pattern matches for the first time, and all lines after that, including the matched line itself get printed, those before that not.
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
You could use awk (both the default mawk and the GNU gawk version work for this) to filter your file with a single command:
awk '/STRING/{y=1} y' file1.txt > file2.txt
Here, /STRING/{y=1} scans each input line for the regular expression pattern STRING and if it matches, set a variable y to 1. Both the name and value are chosen arbitrarily here, we just use this as a boolean flag to remember if we have seen the pattern you search already or not.
Then, also for each line, after performing the first check for that line, it evaluates the expression y. If it's a truthy value (like e.g. 1 here; while the variable being not defined yet or if it were 0 that would be falsey), awk performs the default action for that line, because we didn't specify any after the expression, which is to simply print that line.
That way, the variable gets set when our STRING pattern matches for the first time, and all lines after that, including the matched line itself get printed, those before that not.
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
edited Jan 3 at 19:14
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
answered Jan 3 at 16:37
Byte CommanderByte Commander
63.7k26173292
63.7k26173292
add a comment |
add a comment |
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