How do I grep multiple files in Unix?

How do I grep multiple files 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.

How do I combine two grep commands?

Two possibilities:

1. Group them: { grep ‘substring1’ file1.txt grep ‘substring2’ file2.txt } > outfile.txt.
2. Use the appending redirection operator >> for the second redirection: grep ‘substring1’ file1.txt > outfile.txt grep ‘substring2’ file2.txt >> outfile.txt.

How do you grep multiple lines after a match?

For BSD or GNU grep you can use -B num to set how many lines before the match and -A num for the number of lines after the match. If you want the same number of lines before and after you can use -C num . This will show 3 lines before and 3 lines after.

How do I grep a string into all files in a directory?

To grep All Files in a Directory Recursively, we need to use -R option. When -R options is used, The Linux grep command will search given string in the specified directory and subdirectories inside that directory. If no folder name is given, grep command will search the string inside the current working directory.

How do I grep multiple strings from a file?

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.

How do I grep a string in multiple directories?

2 Answers

1. -R means recursive, so it will go into subdirectories of the directory you’re grepping through.
2. –include=”*.c” means “look for files ending in .c “
3. –exclude-dir={DEF} means “exclude directories named DEF .
4. writeFile is the pattern you’re grepping for.

Can grep have multiple strings?

You can grep multiple strings in different files and directories. The tool prints all lines that contain the words you specify as a search pattern.

How do you grep the next 4 lines?

The -B 4 tells grep to also show the 4 lines before the match. Alternatively, to show the log lines that match after the keyword, use the -A parameter. In this example, it will tell grep to also show the 2 lines after the match.

How do you grep multiple words in one line in Unix?