Since Linux only searches from the current working directory and lower for a file, you might need to navigate to an appropriate directory in which to begin a search. If you need to find types other than ASCII, simply replace grep ASCII with other type, like grep "PDF document, version 1.If you don't see a file or directory that you know should be there, chances are that you need to broaden the directory scope of the search. If it starts with - like -c which could otherwise be interpreted - for bash ensures whatever comes after it is an argument even.xargs, using -0 option, reads them null separated, -I each record and uses as positional parameter/args to bash.find prints results null separated, this is good to escapeįilenames with spaces and meta-characters in it.file checks type of file by magic byte, grep checks if ASCIIĮxists, if so, then after & your next command executes.Make xargs feed each item as a line into one liner bash.if that file contains given string, cat the entire file or look for a secondary string in it. You can modify the part after & to call some other script or do some other stuff inline as well, i.e. Legend: $ is the interactive shell prompt where we enter our commands Xargs -0 -I bash -c 'file | grep ASCII &>/dev/null & echo "file is ASCII: - file is ASCII. If you are interested in finding any file type by their magic bytes using the awesome file utility combined with power of find, this can come in handy: $ # Let's make some test files will return true when the grep command returns true. NOW, the expression to the right of find. It takes the output of the find command (a string that is the filetype of a single file) and tests it to see if it contains the string 'ASCII'. Pipe take the output of whatever is on the left and uses it as input to whatever is on the right. See the manual for 'find' for more explanation if you need it by running man find. " " = this is required by find and is the punctuation mark at the end of our -exec command. In other words, we're just asking for the system to output a string for every file in the directory. It's like calling a function within a function.įile to act as an empty variable, or parameter. exec = this flag is an option within the find command that allows us to use the result of some other command as the search expression. If True, the file name will get printed out. The most important thing to understand is that everything after that first bit is going to be evaluated as either True or False. The find command prints out the filename of any file that matches the 'expression', or whatever comes after the path, which in our case is the current directory or. = look through every file in this directory. Looks complicated, but not bad when we break it down:įind. So how can we string these together in a single line? There are multiple ways to do it, but I find that doing it in order of our pseudo-code makes the most sense (especially to a beginner like me). Grep will look for the keyword 'ASCII' in the output from file In our case, we're looking for a return of 'ASCII text' To achieve this, we can use three UNIX commands: find, file, and grep.įind will check every file in the directory.įile will give us the filetype. If it's an ASCII file, then print out the filename If you were to write out the problem in steps, it would look like this: // For every file in this directory Here's a simplified version with extended explanation for beginners like me who are trying to learn how to put more than one command in one line.
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