Grep unique values in a certain column1/22/2024 The & will make sure that the file doesn't get overwritten when there is a problem. If you want to remove the first line inside the file, you should use: tail -n +2 "$FILE" > "$FILE.tmp" & mv "$FILE.tmp" "$FILE" cut -d '' -f 3 customer cuts column 3 from all the rows in customer file. grep '1001' customer grabs rows starting with 1001, from a file named customer. I can grep for a certain row, and I can cut for a certain column, but I can't figure out how to do both. Shell redirects stdout of the tail process to $FILE I have a file with multiple rows, each row delimited with into multiple columns.The reason is that the redirection ( >) happens before tail is invoked by the shell: Note: You may be tempted to use # THIS WILL GIVE YOU AN EMPTY FILE!īut this will give you an empty file. Very briefly, foverlaps() collapses the two-column interval in y to one-column of unique values. I wonder how they managed that tail should just read a file line by line while sed does pretty complex operations involving interpreting a script, applying regular expressions and the like. The BSD version can be much slower than sed, though. cat sample.csv ID,Name,no 1,AAA,1 2,BBB,1 3,AAA,1 4,BBB,1 cut -d, -f2 sample.csv sort uniq this gives only the 2nd column values Name AAA BBB How to I get all the columns of CSV along with this 2. Check the FreeBSD or OS X man pages for more. To get all the columns in a CSV file based on unique values of particular column. tail is also available on BSD and the -n +2 flag is consistent across both tools. tail -n +1 would print the whole file, tail -n +2 everything but the first line, etc. The + sign kind of inverts the argument and make tail print anything but the first x-1 lines. tail -n 5 would give you the last 5 lines of the input.
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