How do I grep for multiple words in Linux?
How do I grep for multiple patterns?
- Use single quotes in the pattern: grep ‘pattern*’ file1 file2.
- Next use extended regular expressions: egrep ‘pattern1|pattern2’ *. py.
- Finally, try on older Unix shells/oses: grep -e pattern1 -e pattern2 *. pl.
- Another option to grep two strings: grep ‘word1|word2’ input.
How do I grep a specific string in Linux?
Searching for Patterns With grep
- To search for a particular character string in a file, use the grep command.
- grep is case sensitive; that is, you must match the pattern with respect to uppercase and lowercase letters:
- Note that grep failed in the first try because none of the entries began with a lowercase a.
How do you grep multiple lines after a match? Use the -A argument to grep to specify how many lines beyond the match to output. And use -B n to grep lines before the match. And -C in grep to add lines both above and below the match!
How do you grep words with spaces? For any specific space character, you just use it. If you want to allow for ANY space character (tab, space, newline, etc), then if you have a “grep” that supports EXTENDED regular expressions (with the ‘-E’ option), you can use ‘[[:space:]]’ to represent any space character. which will match exactly that.
How do I grep for multiple words in Linux? – Additional Questions
How do I grep a list of strings in a file?
The basic grep syntax when searching multiple patterns in a file includes using the grep command followed by strings and the name of the file or its path. The patterns need to be enclosed using single quotes and separated by the pipe symbol. Use the backslash before pipe | for regular expressions.
What is the difference between grep and Egrep?
The main difference between grep and egrep is that grep is a command that allows searching content according to the given regular expression and displaying the matching lines while egrep is a variant of grep that helps to search content by applying extended regular expressions to display the machining lines.
How do I use special characters in grep search?
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 you grep case sensitive?
4.1 Searching for Patterns with grep
- To search for a particular character string in a file, use the grep command.
- grep is case-sensitive; that is, you must match the pattern with respect to uppercase and lowercase letters:
- Note that grep failed in the first try because none of the entries began with a lowercase “a.”
How do you grep a blank line in Unix?
To match empty lines, use the pattern ‘ ^$ ‘. To match blank lines, use the pattern ‘ ^[[:blank:]]*$ ‘. To match no lines at all, use the command ‘ grep -f /dev/null ‘.
How do you grep a tab character?
4 Answers
- tell grep to use the regular expressions as defined by perl (perl has t as tab): grep -P “t” foo.txt.
- use printf to print a tab character for you: grep “$(printf ‘t’)” foo.txt.
- use the literal tab character: grep “^V<tab>” foo.txt.
- use the ansi c quoting feature of bash: grep $’t’ foo.txt.
- use awk: awk ‘/t/’
How do you grep regex?
grep is one of the most useful and powerful commands in Linux for text processing. grep searches one or more input files for lines that match a regular expression and writes each matching line to standard output.
Special Backslash Expressions.
| Expression |
Description |
| w |
Match a word. |
| s |
Match a space. |
What does this regex do?
Short for regular expression, a regex is a string of text that allows you to create patterns that help match, locate, and manage text. Perl is a great example of a programming language that utilizes regular expressions.
How do I replace a tab with spaces?
First set the “replace by spaces” setting in Preferences -> Language Menu/Tab Settings .
Go to:
- Menu Settings -> Preferences.
- Choose Tab Settings.
- Choose your language type (e.g. Python)
- Select checkbox ‘Use default value’
- Select checkbox ‘Replace by space’
How do I replace a tab with 4 spaces in vim?
replace space by tab
in vim you can do this: # first in . vimrc set up :set expandtab :set tabstop=4 # or you can do this :set tabstop=4 shiftwidth=4 expandtab # then in the py file in command mode, run :retab!
How do I change tabs with spaces in Linux?
On linux:
- Replace all tabs with 1 hyphen inplace, in all *.txt files: sed -i $’s/t/-/g’ *.txt.
- Replace all tabs with 1 space inplace, in all *.txt files: sed -i $’s/t/ /g’ *.txt.
- Replace all tabs with 4 spaces inplace, in all *.txt files: sed -i $’s/t/ /g’ *.txt.
How do I convert tab to space in vi?
If you enable expandtab again :set expandtab then and run the :retab! command then all the tabs becomes spaces. If you want to do this for selected text then first select the text in visual mode.
How do I set tab to two spaces in vim?
vim tab 2 spaces
- set smartindent.
- set tabstop=2.
- set expandtab.
- set shiftwidth=2.
How many spaces is a tab?
Generally, a tab is the same width as 4 to 5 spaces provided the font being used equally sizes each character. For example, the Courier font’s tab equals 5 spaces, whereas the Arial font is 11 spaces to each tab when the font size for both is set to 12.
How do I show tabs and spaces in vim?
If you don’t want to show all the whitespaces of the text on the Vim editor of your system, you need to turn the “hls” command off. For that purpose, go to the normal mode first. Press the “;” character, and you will be in the command mode.
How do I see tabs in vi?
tab:xy Two characters to be used to show a tab. The first char is used once. The second char is repeated to fill the space that the tab normally occupies. “tab:>-” will show a tab that takes four spaces as “>—“.
How do I search for tabs in vi?
Searching for the Tab Character
In NORMAL mode, type /t and hit <Enter> . It will search for the Tab character ( t ) and highlight the results.
