Finding Files with find and xargs

ls only shows you what is in one directory. When you need to search an entire tree - "every .log file anywhere under /var" - that is a job for find.

find: searching by name

find /var -name "*.log"        # every .log file under /var, at any depth
find . -name "*.txt"           # every .txt file under the current directory

find prints one path per line, which makes it perfect for feeding into another command.

xargs: turning a list into a command

Piping a list of paths into a command like rm does not work directly, because rm expects paths as arguments, not as piped-in text. xargs bridges that gap: it reads whitespace-separated tokens from stdin and runs a command once for each one, appending the token as an argument.

find /var -name "*.log" | xargs rm     # delete every match
find . -name "*.tmp" | xargs cat       # print the contents of every match

This "find it, then xargs it" pattern is one of the most useful idioms in the entire command line - it turns a search into a bulk operation with almost no code.

Try it

mkdir -p /var/log/app
echo "boot ok" > /var/log/app/one.log
echo "boot ok" > /var/log/app/two.log
find /var -name "*.log"
find /var -name "*.log" | xargs rm
find /var -name "*.log"

The list is empty on the last line - every match was deleted in one step.

Further reading

• "The Linux Command Line" by William Shotts (No Starch Press) - its chapter on finding files walks through find's many test expressions (by size, by age, by permissions) well beyond -name.
• "UNIX and Linux System Administration Handbook" by Nemeth, Snyder, Hein, Whaley, and Mackin (Pearson) - shows this exact find | xargs idiom used for real sysadmin cleanup and auditing tasks.