#Unix search for text in files how to#
#Unix search for text in files manual#

Let's run the command with this regular expression, and see what additional matches we can get: And because we're specifying the -i option, ' OUR PRODUCTS' and ' OuRpRoDuCtS will match as well. For instance, ' our amazing products', ' ours, the best-ever products', and even ' ourproducts' will match. *' will match any number of any character. It means 'any character that appears in this place will match.' The asterisk (' *') means 'the preceding character, appearing zero or more times, will match.' So the combination '. ') is interpreted as a single-character wildcard. We can specify this PATTERN instead: 'our.*products'. Let's say you want to find every occurrence of a phrase similar to 'our products' in your HTML files, but the phrase should always start with 'our' and end with 'products'. Regular expressions use special characters in the PATTERN string to match a wider array of strings. (That's what the 're' in 'grep' stands for). The true power of grep is that it can match regular expressions. Using regular expressions to perform more powerful searches

Notice that the directory name is included for any matching files that are not in the current directory. Let's change our FILE name to an asterisk (' *'), so that it matches any file or directory name, and not only HTML files: We can extend our search to subdirectories and any files they contain using the -r option, which tells grep to perform its search recursively. Notice that each line starts with the specific file where that match occurs. When the command is executed, the shell expands the asterisk to the name of any file it finds (in the current directory) which ends in '. Instead of specifying product-listing.html, we can use an asterisk (' *') and the. If we have multiple files to search, we can search them all using a wildcard in our FILE name. Searching multiple files using a wildcard Using the -i option, grep finds a match on line 23 as well. What if 'our products' appears at the beginning of a sentence, or appears in all uppercase? We can specify the -i option to perform a case-insensitive match: Performing case-insensitive grep searches Our matching line is prefixed with ' 18:' which tells us this corresponds to line 18 in our file. If we specify the -n option, grep will prefix each matching line with the line number: It will be even more useful if we know where the matching line appears in our file. Viewing line numbers of successful matches If we use the -color option, our successful matches will be highlighted for us: For more information, see: Regular expression quick reference. Other characters have special meanings, however - some punctuation marks, for example. In the above example, all the characters we used (letters and a space) are interpreted literally in regular expressions, so only the exact phrase will be matched.

#Unix search for text in files manual#

Take a look at the grep manual and the sed manual for more information.The PATTERN is interpreted by grep as a regular expression. For example, say you want to skip the tests/ directory: grep -RiIl -exclude-dir=tests 'search' | xargs sed 's/search/replace/g'Д®xclude multiple directories by wrapping them into curly braces, like so: grep -RiIl -exclude-dir= 'search' | xargs sed 's/search/replace/g'Д«oth grep and sed support regular expressions, so you can search with grep given a specific pattern and then replace the text with sed given another one. You can add the -exclude-dir= parameter to grep if you want to skip a specific directory while searching for files.

#Unix search for text in files how to#

replace), the g instructs the command to replace all occurrences.ДЇine tuning 1: how to exclude directories while searching

s/search/replace/g - this is the substitution command.

In the current snippet I'm using it to replace text with the following parameters: Sed is a glorious Unix utility that transforms text. So in this example the output of grep is passed to the next command sed as its argument. This is a little command-line utility that takes what receives in input and passes it as argument to another program.

l - print results as a simple list of file names.

R - perform a recursive search, also across symbolic links.

Here I'm invoking it with the following parameters: Grep is a utility for searching for strings through multiple text files. Let me now dissect it and take a quick look at the different tools in use. Assuming that you want to search for the string search through multiple files and replace it with replace, this is the one-liner: grep -RiIl 'search' | xargs sed -i 's/search/replace/g' After a bit of research I've come up with a nice solution. Often times I need to search and replace a string of text across multiple files in my Linux box.