How do you grep the last occurrence in Unix?

How do I grep the latest file in Unix?


  1. Grep. -R search recursively and follow symlinks. …
  2. Xargs. xargs will run stat against each line of input coming from STDIN , which is the output from grep.
  3. Grep. -P allow perl regexp in PATTERN . …
  4. Sed. -r enables support for extended regular expressions. …
  5. Tr. -d delete the character instead of replacing it. …
  6. Awk. …
  7. Sort.

How do you find the last occurrence of a character in a string in Linux?

If you like to find the exact index of the last occurrence of the character in the string, then you use the length function in the awk command.

How do you find the occurrence of a word in Unix?

Using the -o option tells grep to output each match on its own line, no matter how many times the match was found in the original line. wc -l tells the wc utility to count the number of lines. After grep puts each match in its own line, this is the total number of occurrences of the word in the input.

How do I grep first occurrence in Unix?

4 Answers. If you really want return just the first word and want to do this with grep and your grep happens to be a recent version of GNU grep , you probably want the -o option. I believe you can do this without the -P and the b at the beginning is not really necessary. Hence: users | grep -o “^w*b” .

How do I find the last 10 files in UNIX?

It is the complementary of head command. The tail command, as the name implies, print the last N number of data of the given input. By default it prints the last 10 lines of the specified files. If more than one file name is provided then data from each file is precedes by its file name.

How do I grep a timestamp?

I suggest you do:

  1. Press CTRL + ALT + T .
  2. Run the command ( -E for extended regex): sudo grep -E ‘2019-03-19T09:3[6-9]’ <file or file_path>

What is the use of awk in Linux?

Awk is a utility that enables a programmer to write tiny but effective programs in the form of statements that define text patterns that are to be searched for in each line of a document and the action that is to be taken when a match is found within a line. Awk is mostly used for pattern scanning and processing.

How do you change the last character of a string in Unix?

To index to the last char you use ${str:0:$((${#str}-1))} (which is just str:0:to_last-1 ) so to replace the last character, you just add the new last character at the end, e.g. There are always multiple ways to skin-the-cat in bash.

What is the purpose of in Unix?

Unix is an operating system. It supports multitasking and multi-user functionality. Unix is most widely used in all forms of computing systems such as desktop, laptop, and servers. On Unix, there is a Graphical user interface similar to windows that support easy navigation and support environment.

How do you grep in Unix?

To search multiple files with the grep command, insert the filenames you want to search, separated with a space character. The terminal prints the name of every file that contains the matching lines, and the actual lines that include the required string of characters. You can append as many filenames as needed.

Does grep support regex?

Grep Regular Expression

A regular expression or regex is a pattern that matches a set of strings. … GNU grep supports three regular expression syntaxes, Basic, Extended, and Perl-compatible. In its simplest form, when no regular expression type is given, grep interpret search patterns as basic regular expressions.

How do you count grep?

Using grep -c alone will count the number of lines that contain the matching word instead of the number of total matches. The -o option is what tells grep to output each match in a unique line and then wc -l tells wc to count the number of lines. This is how the total number of matching words is deduced.

How do I grep a file in Linux?

How to use the grep command in Linux

  1. Grep Command Syntax: grep [options] PATTERN [FILE…] …
  2. Examples of using ‘grep’
  3. grep foo /file/name. …
  4. grep -i “foo” /file/name. …
  5. grep ‘error 123’ /file/name. …
  6. grep -r “” /etc/ …
  7. grep -w “foo” /file/name. …
  8. egrep -w ‘word1|word2’ /file/name.
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