Finding and Searching

find . -name "*.log"                    # by filename (case-sensitive)
find . -iname "*.LOG"                   # case-insensitive
find /etc -type f                       # regular files only
find /etc -type d                       # directories only
find . -type l                          # symlinks only
find . -empty                           # empty files and dirs
find . -size +10M                       # larger than 10 MB
find . -size -1k                        # smaller than 1 KB
find . -size 100c                       # exactly 100 bytes
find . -mtime -7                        # modified in last 7 days
find . -mtime +30                       # modified more than 30 days ago
find . -newer ref.txt                   # newer than ref.txt
find . -user alice                      # owned by alice
find . -group staff                     # owned by group staff
find . -perm 644                        # exact permissions
find . -perm /u+x                       # any executable by owner
find . -maxdepth 2                      # limit search depth
find . -mindepth 1 -maxdepth 1         # immediate children only

find . -name "*.tmp" -delete            # delete matches
find . -name "*.sh" -exec chmod +x {} \;   # exec per file
find . -name "*.log" -exec grep -l "error" {} \;
find . -name "*.bak" -exec rm {} +     # exec batched (faster)
find . -name "*.txt" | xargs wc -l     # pipe to xargs
find . -name "*.txt" -print0 | xargs -0 grep "TODO"  # handle spaces in names

find . -name "*.js" -not -path "*/node_modules/*"
find . \( -name "*.log" -o -name "*.tmp" \) -mtime +7
find . -name "*.conf" -and -user root

locate nginx.conf           # search indexed database
locate -i readme            # case-insensitive
locate -c "*.log"           # count matches
sudo updatedb               # rebuild index (or runs nightly via cron)

which python3           # path of first match in $PATH
which -a python3        # all matches in $PATH
whereis python3         # binary + man + source paths
type -a ls              # alias, function, or binary?
command -v python3      # POSIX-safe which (exit 0/1)

grep -r "secret" /etc/          # recursive
grep -rn "TODO" ./src/          # with line numbers
grep -rl "error" ./logs/        # filenames only
grep -ri "password" /etc/       # case-insensitive recursive
grep --include="*.py" -r "import" .   # filter by filename pattern
grep --exclude-dir=".git" -r "fix" .  # exclude directories

rg "error" ./logs/              # search recursively (respects .gitignore)
rg -i "warning" .               # case-insensitive
rg -n "def " app.py             # line numbers
rg -l "TODO" .                  # filenames only
rg -t py "import" .             # filter by file type
rg -g "*.md" "section" .        # glob filter
rg "error" -A 2 -B 1            # context lines
rg --no-ignore "secret" .       # ignore .gitignore

fd "\.log$"                     # regex on filename
fd -t f "config"                # files only
fd -e log                       # by extension
fd -H "^\.env"                  # include hidden files
fd --exclude node_modules "*.js"
fd -x rm {}                     # execute per result

# Search compressed files
zgrep "error" access.log.gz
zcat file.gz | grep "pattern"

# Binary files
strings binary | grep "VERSION"
hexdump -C file | head

# Search man pages
man -k "copy file"          # apropos keyword
mandb                       # rebuild man database