4 Answers. Explanations: The regex /b[0-9]/b will match a single digit surrounded by word boundary character, the -o option is used to print only that result and not the whole line as the default behavior does. This will output all the numbers composed of a single digit.

grep -r -L “[^0-9 ]” . [^0-9 ] will match anything that doesn’t contain digits or spaces (thought that would be fitting or else all files that contain spaces and number would be discarded). The -L flag is –files-without-match , so this basically gives you files that DO contain digits or spaces.

How do I grep for multiple patterns?

1. Use single quotes in the pattern: grep ‘pattern*’ file1 file2.
2. Next use extended regular expressions: egrep ‘pattern1|pattern2’ *. py.
3. Finally, try on older Unix shells/oses: grep -e pattern1 -e pattern2 *. pl.
4. Another option to grep two strings: grep ‘word1/|word2’ input.

This matches four digits and the non-digit character–or beginning or end of the line–surrounding them. Specifically: [0-9] matches any digit (like [[:digit:]] , or /d in Perl regular expressions) and {4} means “four times.” So [0-9]{4} matches a four-digit sequence.

/s seems to work for whitespace, and /S seems to work for non-whitespace, but it includes all whitespace characters (spaces AND tabs) and it doesn’t work if I put it in brackets, treating the backslash and the /s as separate characters. You’ll need to get more clear with your question.

Show Line Numbers The -n ( or –line-number ) option tells grep to show the line number of the lines containing a string that matches a pattern. When this option is used, grep prints the matches to standard output prefixed with the line number.

Both egrep and fgrep are derived from the base grep command. The “egrep” stands for “extended grep” while the fgrep stands for “fixed-string grep.” 2.An egrep command is used to search for multiple patterns inside a file or other kind of data repository while frgrep is used to look for strings.

GNU Grep on Mac GNU grep can be installed on the Mac by means of homebrew. After brew has installed grep, you have two versions of the command. The BSD version is called grep and the GNU version is called ggrep . The examples that follow use the GNU version of grep, so Mac users should use the ggrep command.

The first could be written grep ‘ ‘ a. txt , the second altered similarly. Note that /s also matches tab, return, vertical tab, form feed and, technically, newline. If you want to only match space and tab, use [[:blank:]] or [ /t] .

I found out that in grep, it is actually [ [:digit:]] that matches numbers. While I managed to understand why there are double brackets, I cannot figure out a way to match with multiple integers. It will fail to match anything.

It is also often required to grep a file for multiple patterns – when it is needed to find all the lines in a file, that contain not one, but several patterns. Note, that you can both find the lines in a file that match multiple patterns in the exact order or in the any order.

grep ‘extra|value’ /home/test/Desktop/sample.txt To search for more than two words, keep adding them in the same manner. For example, to search for three words, add the desired string of characters followed by a backslash and pipe:

The name stands for Global Regular Expression Print. By using the grep command, you can customize how the tool searches for a pattern or multiple patterns in this case. You can grep multiple strings in different files and directories.