A, cut
Specify the delimiter, cutting file;
Common parameters: -d (delimiter) specify the delimiter
-f specify which column to extract
-out-delimeter = 'xx' output by the delimiter want for their own replacement delimiters
Limitations: 1, -d can not specify a plurality of separators;
2, can not do high-level formatted output, we need to master awk.
Example:
cut -d '' -f 1 / etc / fstab // take the first column
cut -d '' -f 1,3 / etc / fstab // get column 3
cut -d '' -f 1-3 / etc / fstab // taken columns 1-3
cut -d [:] -f 1 / etc / passwd // designated as a space or a colon delimiter
Two, sort
When sorting sort, a default view of characters (including alphanumeric, spaces, and special characters), the ASCII code ordering (not ordered according to numerical values)
Common parameters:
-r reverse order
-F ignores case characters
-t DELIMITER specified field delimiter
The first columns specified field to sort -k
-n specify numerical values are sorted
-u uniq sort deduplication, do not show repetitive
Three, uniq
Remove duplicate content (and history, as only together content is the continuous repetition)
Common parameters:
-c displays each line repeated many times, figured out
-d display only duplicate rows over
-u display not only duplicate rows
Example:
History | cut -d' ' -f 5 | uniq
History | cut -d' ' -f 5 | sort | uniq -c/-d/-u