fd, grep and sed

These 3 commands are all CLI tools that can enable searching for files, searching for text, find and replace in files

fd

`fd` is a fast, user-friendly alternative to the find command. It has some extra features compared to find such as ignore files in .gitignore, syntax highlighting, faster and more.

fd Options

• -t [f|d] - Specify the type; file or folder

• -e [extension] - Specify the file extension (e.g 'md')

• -x [command] - A command to execute for each found record

Using fd

# Find all folders in current directory
fd --type d

# Find all markdown files in current directory
fd -e md

# Output all log files in current directory
fd -e log -x cat

grep

Use grep to check if a file contains a pattern. You can also output each line that matches with the lines above or below.

grep Options

• -v - Invert match (match lines NOT containing pattern)

• -i - Ignore case

• -c - Count the number of matches

• -r - Recursively search in subdirectories

• -n - Output line number

• -A [number] - Output number of lines after match

• -B [number] - Output number of lines before match

Using grep

# Find the number of occurrences of 'mine' in a file
grep -c 'mine' file.txt

# Find all files containing 'my_variable_name'
grep -r 'my_variable_name' .

# Save into a file all occurrences of 'bob' with 5 lines above and below the match
grep -r -A 5 -B 5 'bob' . > output.txt

sed

Use sed to find and replace text in files.

sed Options

• -i - Edit files in-place

• -e [command] - A command to execute for each found record

Using sed

# Replace all occurrences of 'old' with 'new' in a file
sed -i 's/old/new/g' file.txt

# Display the changes:
# Replace (case insensitive) 'OLD' with 'new'
sed -i 's/OLD/new/gi' file.txt

All Together Now

If we put these all together we could create a find and replace for all matches of a pattern in a directory:

# '{}' is the file path passed from fd
fd -e md -x sed -i 's/old/new/g' {}

Display the count of matches for a variable in the current directory:

fd -e md -x grep -c 'my_variable_name' {}

Output the number of files that contains the word 'bob':

fd -t f -x grep -c 'bob' {} | grep -v '^0$' | wc -l