How do I get unique values in Linux?
To find unique occurrences where the lines are not adjacent a file needs to be sorted before passing to uniq . uniq will operate as expected on the following file that is named authors. txt . As duplicates are adjacent uniq will return unique occurrences and send the result to standard output.
How do I grep special characters in Linux?
If you include special characters in patterns typed on the command line, escape them by enclosing them in single quotation marks to prevent inadvertent misinterpretation by the shell or command interpreter. To match a character that is special to grep –E, put a backslash ( ) in front of the character.
How do I grep a value in Linux?
How to use the grep command in Linux
- Grep Command Syntax: grep [options] PATTERN [FILE…] …
- Examples of using ‘grep’
- grep foo /file/name. …
- grep -i “foo” /file/name. …
- grep ‘error 123’ /file/name. …
- grep -r “192.168.1.5” /etc/ …
- grep -w “foo” /file/name. …
- egrep -w ‘word1|word2’ /file/name.
How do I find unique records in Unix?
How to find duplicate records of a file in Linux?
- Using sort and uniq: $ sort file | uniq -d Linux. …
- awk way of fetching duplicate lines: $ awk ‘{a[$0]++}END{for (i in a)if (a[i]>1)print i;}’ file Linux. …
- Using perl way: …
- Another perl way: …
- A shell script to fetch / find duplicate records:
What does Uniq do in Linux?
The uniq command can count and print the number of repeated lines. Just like duplicate lines, we can filter unique lines (non-duplicate lines) as well and can also ignore case sensitivity. We can skip fields and characters before comparing duplicate lines and also consider characters for filtering lines.
How do you grep symbols?
For example, grep uses a dollar sign as a special character matching the end of a line — so if you actually want to search for a dollar sign, you have to precede it by a backslash (and include the whole search string in single quotes). But fgrep lets you just type in that dollar sign.
How do you grep double quotes in Linux?
So, you have to use different approaches:
- Use double quotes: grep “‘type’ => ‘select'” file.
- If you prefer needlessly complex solutions: grep “‘”type”‘” => “‘”select”‘” file.
- You can always search for any single character instead of specifying the single quotes: grep ‘.type. => . select.’ file.
How do you type special characters in Unix?
About Unix standard multi-key support
If a character is unavailable on the keyboard, you can insert the character by pressing the special Compose key followed by a sequence of two other keys. See the table below for the keys used to insert various characters. Note that in Amaya you can change the order of the two keys.
What is grep in Linux command?
You use the grep command within a Linux or Unix-based system to perform text searches for a defined criteria of words or strings. grep stands for Globally search for a Regular Expression and Print it out.
What is PS EF command in Linux?
This command is used to find the PID (Process ID, Unique number of the process) of the process. Each process will have the unique number which is called as PID of the process.