awk:awk_patterns
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| awk:awk_patterns [2020/05/04 23:16] – created peter | awk:awk_patterns [2022/06/13 09:51] (current) – [Match using Multiple Patterns] peter | ||
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| ====== AWK - AWK Patterns ====== | ====== AWK - AWK Patterns ====== | ||
| + | |||
| + | Assuming a file exists with the following contents: | ||
| + | |||
| + | < | ||
| + | 10 | ||
| + | 11 | ||
| + | 12 | ||
| + | 13 | ||
| + | 14 | ||
| + | 48 | ||
| + | </ | ||
| + | |||
| + | ---- | ||
| ===== Matching Patterns ===== | ===== Matching Patterns ===== | ||
| - | To only print out lines which match a specific search criteria, issue the following command: | + | To only print out lines which **match** a specific search criteria: |
| - | < | + | < |
| awk '/45/ {print $2, | awk '/45/ {print $2, | ||
| </ | </ | ||
| - | which will display something like: | + | returns: |
| < | < | ||
| Line 16: | Line 29: | ||
| </ | </ | ||
| - | This only prints out the lines from the file which contained the number 45. | + | <WRAP info> |
| + | **NOTE: | ||
| + | </ | ||
| ---- | ---- | ||
| Line 22: | Line 38: | ||
| ===== Multi-line Output with Patterns ===== | ===== Multi-line Output with Patterns ===== | ||
| - | To output onto multiple lines, issue the following command: | + | To output onto multiple lines: |
| - | < | + | < |
| awk '/45/ {print $2,$3,$4 ; print $1, $5}' test.txt | awk '/45/ {print $2,$3,$4 ; print $1, $5}' test.txt | ||
| </ | </ | ||
| - | which will display something like: | + | returns: |
| < | < | ||
| Peter Terence Roux | Peter Terence Roux | ||
| 10 45 | 10 45 | ||
| - | Virginia | + | Virginia |
| 11 45 | 11 45 | ||
| </ | </ | ||
| - | Again, this only prints out the lines from the file which contained the number 45. | + | <WRAP info> |
| + | **NOTE: | ||
| - | But also prints out a 2nd line because of the use of the semicolon. | + | * But also prints out a 2nd line because of the use of the semicolon. |
| - | A semicolon does not have to be used to allow using multiple commands. | + | </ |
| - | < | + | <WRAP info> |
| + | **NOTE: | ||
| + | |||
| + | For instance issue the following command instead: | ||
| + | |||
| + | < | ||
| awk '/45/ {print $2,$3,$4} {print $1, $5}' test.txt | awk '/45/ {print $2,$3,$4} {print $1, $5}' test.txt | ||
| </ | </ | ||
| - | which will display something like: | + | returns: |
| < | < | ||
| Peter Terence Roux | Peter Terence Roux | ||
| 10 45 | 10 45 | ||
| - | Virginia | + | Virginia |
| 11 45 | 11 45 | ||
| 12 5 | 12 5 | ||
| Line 62: | Line 84: | ||
| This time an altogether different result is produced, than when a semicolon was used. | This time an altogether different result is produced, than when a semicolon was used. | ||
| - | The reason for this is that the pattern that is used, /45/ is only applied to the command immediately following it. In this example, this was only against fields $2, $3 and $4. | + | The reason for this is that the pattern that is used, **/45/** is only applied to the command immediately following it. In this example, this was only against fields $2, $3 and $4. |
| The 2nd print statement is not affected by the pattern and would apply to all fields in the input file. | The 2nd print statement is not affected by the pattern and would apply to all fields in the input file. | ||
| + | </ | ||
| ---- | ---- | ||
| Line 72: | Line 95: | ||
| To search for more than one pattern match at a time, issue the following command: | To search for more than one pattern match at a time, issue the following command: | ||
| - | < | + | < |
| awk '/ | awk '/ | ||
| </ | </ | ||
| - | which will display something like: | + | returns: |
| < | < | ||
| Line 85: | Line 108: | ||
| </ | </ | ||
| - | The pipe symbol | is used to provide multiple patterns. | + | <WRAP info> |
| + | **NOTE: | ||
| + | </ | ||
| ---- | ---- | ||
| Line 91: | Line 117: | ||
| ===== Match against specific field ===== | ===== Match against specific field ===== | ||
| - | To restrict the match to only a specific field, issue the following command: | + | To restrict the match to only a specific field: |
| - | < | + | < |
| - | awk '$5 ~ /45|48/ {print $2, | + | awk '$5 ~ /45|48/ {print $2, |
| </ | </ | ||
| - | which will display something like: | + | returns: |
| < | < | ||
| Line 105: | Line 131: | ||
| </ | </ | ||
| - | Note that this time Adam Ridley is not displayed even though the source file has a 48 as part of his record. | + | <WRAP info> |
| + | **NOTE: | ||
| - | The tilda ~ ties the match to a specific field. | + | * The tilda ~ ties the match to a specific field. |
| + | |||
| + | </ | ||
| ---- | ---- | ||
| Line 113: | Line 142: | ||
| ===== Match not against a specific field ===== | ===== Match not against a specific field ===== | ||
| - | To have the match be the opposite of matching a specific field, issue the following command: | + | To have the match be the opposite of matching a specific field: |
| - | < | + | < |
| awk '$5 !~ /45|48/ {print $2, | awk '$5 !~ /45|48/ {print $2, | ||
| </ | </ | ||
| - | which will display something like: | + | returns: |
| < | < | ||
| Line 127: | Line 156: | ||
| </ | </ | ||
| - | The **exclamation mark** and **tilda** (!~) together informs to not match to a specific field. | + | <WRAP info> |
| + | **NOTE: | ||
| + | </ | ||
| ---- | ---- | ||
| Line 133: | Line 165: | ||
| ===== Match in a Range ===== | ===== Match in a Range ===== | ||
| - | To have the match be the opposite of matching a specific field, issue the following command: | + | To have the match be the opposite of matching a specific field: |
| - | < | + | < |
| - | awk '/ | + | awk '/ |
| </ | </ | ||
| - | which will display something like: | + | returns: |
| < | < | ||
| Line 148: | Line 180: | ||
| </ | </ | ||
| - | This finds all fields with values between 42 and 48. | + | <WRAP info> |
| + | **NOTE: | ||
| + | </ | ||
| ---- | ---- | ||
awk/awk_patterns.1588634174.txt.gz · Last modified: 2020/07/15 09:30 (external edit)