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awk print condtion

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When i was debugging a file which was written by others, I found one line

psql -U crmlocal -h $2 -p 5432 mydb -c "set search_path=$3;$4" | awk 'NR>3 {print l} {l=$0}'

I don't know what

awk 'NR>3 {print l} {l=$0}' 

does this line actually do. Can anyone explain what does this line mean? {print l}

awk

share|improve this question

edited 9 mins ago

Inian

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Hari BharathiHari Bharathi

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0

When i was debugging a file which was written by others, I found one line

psql -U crmlocal -h $2 -p 5432 mydb -c "set search_path=$3;$4" | awk 'NR>3 {print l} {l=$0}'

I don't know what

awk 'NR>3 {print l} {l=$0}' 

does this line actually do. Can anyone explain what does this line mean? {print l}

awk

share|improve this question

edited 9 mins ago

Inian

7,2051717 silver badges3636 bronze badges

asked 22 mins ago

Hari BharathiHari Bharathi

111 bronze badge

New contributor

Hari Bharathi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment
 | 

When i was debugging a file which was written by others, I found one line

psql -U crmlocal -h $2 -p 5432 mydb -c "set search_path=$3;$4" | awk 'NR>3 {print l} {l=$0}'

I don't know what

awk 'NR>3 {print l} {l=$0}' 

does this line actually do. Can anyone explain what does this line mean? {print l}

awk

share|improve this question

edited 9 mins ago

Inian

7,2051717 silver badges3636 bronze badges

asked 22 mins ago

Hari BharathiHari Bharathi

111 bronze badge

New contributor

Hari Bharathi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

psql -U crmlocal -h $2 -p 5432 mydb -c "set search_path=$3;$4" | awk 'NR>3 {print l} {l=$0}'

awk 'NR>3 {print l} {l=$0}' 

share|improve this question

edited 9 mins ago

Inian

7,2051717 silver badges3636 bronze badges

asked 22 mins ago

Hari BharathiHari Bharathi

111 bronze badge

New contributor

Hari Bharathi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

edited 9 mins ago

Inian

7,2051717 silver badges3636 bronze badges

asked 22 mins ago

Hari BharathiHari Bharathi

111 bronze badge

New contributor

Hari Bharathi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

edited 9 mins ago

Inian

7,2051717 silver badges3636 bronze badges

edited 9 mins ago

Inian

7,2051717 silver badges3636 bronze badges

asked 22 mins ago

Hari BharathiHari Bharathi

111 bronze badge

New contributor

Hari Bharathi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 22 mins ago

Hari BharathiHari Bharathi

111 bronze badge

1 Answer
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1

A simpler input to explain the command:

$ seq 6 | awk 'NR>3 {print l} {l=$0}'

3

4

5

• 
  NR is a special variable that has the value of current record number (same as line number in this case)
  
  
  
  
  • so NR>3 means line number greater than 3
  
  
  
  


• 
  {l=$0} this is saving contents of current line (special variable $0) to a user defined variable l
  


• 
  NR>3 {print l} when the condition is true, print contents of variable l
  

So, effectively, this code prints all lines from input except first two lines and the last line.

share|improve this answer

answered 14 mins ago

SundeepSundeep

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 | 

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1

A simpler input to explain the command:

$ seq 6 | awk 'NR>3 {print l} {l=$0}'

3

4

5

• 
  NR is a special variable that has the value of current record number (same as line number in this case)
  
  
  
  
  • so NR>3 means line number greater than 3
  
  
  
  


• 
  {l=$0} this is saving contents of current line (special variable $0) to a user defined variable l
  


• 
  NR>3 {print l} when the condition is true, print contents of variable l
  

So, effectively, this code prints all lines from input except first two lines and the last line.

share|improve this answer

answered 14 mins ago

SundeepSundeep

7,78611 gold badge1111 silver badges2828 bronze badges

add a comment
 | 

1

A simpler input to explain the command:

$ seq 6 | awk 'NR>3 {print l} {l=$0}'

3

4

5

• 
  NR is a special variable that has the value of current record number (same as line number in this case)
  
  
  
  
  • so NR>3 means line number greater than 3
  
  
  
  


• 
  {l=$0} this is saving contents of current line (special variable $0) to a user defined variable l
  


• 
  NR>3 {print l} when the condition is true, print contents of variable l
  

So, effectively, this code prints all lines from input except first two lines and the last line.

share|improve this answer

answered 14 mins ago

SundeepSundeep

7,78611 gold badge1111 silver badges2828 bronze badges

add a comment
 | 

A simpler input to explain the command:

$ seq 6 | awk 'NR>3 {print l} {l=$0}'

3

4

5

• 
  NR is a special variable that has the value of current record number (same as line number in this case)
  
  
  
  
  • so NR>3 means line number greater than 3
  
  
  
  


• 
  {l=$0} this is saving contents of current line (special variable $0) to a user defined variable l
  


• 
  NR>3 {print l} when the condition is true, print contents of variable l
  

So, effectively, this code prints all lines from input except first two lines and the last line.

share|improve this answer

answered 14 mins ago

SundeepSundeep

7,78611 gold badge1111 silver badges2828 bronze badges

$ seq 6 | awk 'NR>3 {print l} {l=$0}'

3

4

5

share|improve this answer

answered 14 mins ago

SundeepSundeep

7,78611 gold badge1111 silver badges2828 bronze badges

answered 14 mins ago

SundeepSundeep

7,78611 gold badge1111 silver badges2828 bronze badges

answered 14 mins ago

SundeepSundeep

7,78611 gold badge1111 silver badges2828 bronze badges