Table Of Contents

• Linux File Manipulation
  • File Manipulation
  • File Compression & Chunking
  • File Hashing

---

LINUX FILE MANIPULATION

FILE MANIPULATION

Compare files

diff <FILE_PATH_A> <FILE_PATH_B>

Force recursive deletion of directory

rm -rf <FILE_PATH>

Secure file deletion

shred -f -u <FILE_PATH>

Modify timestamp to match another file

touch -r <ORIGINAL_FILE_PATH> <MOD_FILE_PATH>

Modify file timestamp

touch -t <YYYYMMDDHHMM> <FILE>

Count lines containing specific string

grep -c "<STRING>" <FILE_PATH>

Convert Linux formatted file to Windows compatible text file

awk 'sub("$", "\r")' <SOURCE_FILE_PATH> > <OUTPUT_FILE_PATH>

Convert Windows formatted file to Linux compatible text file

dos2unix <FILE_PATH>

Search current and all subdirectories for all files that end with a specific extension

find . -type f -name "*.<FILE_EXTENSION>"

Search all files (binary and regular files) in current and all subdirectories for a case insensitive phrase

grep -Ria "<SEARCH_PHRASE>"

Return the line count of a target file

wc -l <FILE_PATH>

Search for setuid files

find / -perm -4000 -exec ls -ld {} \;

Determine file type

file <FILE_PATH>

Set/Unset immutable file

chattr +i <FILE_PATH>
chattr -i <FILE_PATH>

Generate random file (example 3M file)

dd if=/dev/urandom of=<OUTPUT_FILE_PATH> bs=3145728 count=100

FILE COMPRESSION & CHUNKING

Pack/unpack (archive) files using tar

# Compress:
tar -cf <OUTPUT_FILE>.tar <INPUT_PATH>
# Extract:
tar -xf <FILE_PATH>.tar

Compress and extract a .gz file using tar

# Compress:
tar -czf <OUTPUT_FILE>.tar.gz <INPUT_PATH>
# Extract:
tar -xzf <FILE_PATH>.tar.gz

Compress and extract a .bz2 file using tar

# Compress:
tar -cjf <OUTPUT_FILE>.tar.bz2 <INPUT_PATH>
# Extract:
tar -xjf <FILE_PATH>.tar.bz2

Compress and extract using gzip

# Compress:
gzip <INPUT_PATH>
# Extract:
gzip -d <FILE_PATH>.gz

Compress and extract using zip

# Compress:
zip -r <OUTPUT_FILE>.zip <INPUT_PATH>
# Extract:
unzip <FILE_PATH>

Pack an executable using UPX

upx -9 -o <OUTPUT_FILE> <INPUT_PATH>

Split file into 3k chunks using dd

dd if=<INPUT_PATH> bs=4M | gzip -c | split -b 3K - "<OUTPUT_FILE>.chunk"

Restore chunked file using dd

cat <FILE_PATH>.chunk* | gzip -dc | dd of=<OUTPUT_PATH> bs=4M

FILE HASHING

Generate MD5 hash of a file

md5sum <FILE_PATH>

Generate MD5 hash of a string

echo "<STRING>" | md5sum

Generate SHA1 hash of a file

sha1sum <FILE_PATH>