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How can I remove duplicate lines with SED?
Am trying to come to grips with sed. Have read the info page and done some scratching about in a few books, but have not been able to figure out how to remove duplicate lines in a text file, and the example program in the info pages just really didn’t make sense to me. 1. How can I do this using sed?
Is there a way to delete duplicate lines in a file?
Delete duplicate, nonconsecutive and nonempty lines from a file: The one-liner that Andre Miller posted above works except for recent versions of sed when the input file ends with a blank line and no chars. On my Mac my CPU just spins. The explanation is at the very end of the sed FAQ: about how a command to “append the Next line” ought to behave.
When to use sed to replace a multi line string?
Theoretically speaking, there’s no upper bound on the window size of the pattern space. When the size of the file is small, we can practically afford to load the entire file into the pattern space to replace a multi-line string. So, let’s learn this technique of gobbling to solve a few use cases.
How to print the last line in a SED file?
The explanation is at the very end of the sed FAQ: about how a command to “append the Next line” ought to behave. print the last line if the file has an even number of lines. all versions of sed, change a lone “N;” to “$d;N;”.
How to remove lines from a Unix file?
Note: In all the above examples, the sed command prints the contents of the file on the unix or linux terminal by removing the lines. However the sed command does not remove the lines from the source file. To Remove the lines from the source file itself, use the -i option with sed command. > sed -i ‘1d’ file
How to delete lines with multiple keywords in SED?
Similarly, you could run the sed command with option -n and negated p, (!p) command. To delete lines containing multiple keywords, for example to delete lines with the keyword green or lines with keyword violet.
How can I remove patterns using sed command?
I managed to replace patterns with one word “PATTERN” so that it becomes easy to remove them. How can I remove this word? Here are the commands I used: