Files

Encoding

iconv -f cp1251 -t utf8
file -bi

Determine file type

file file_name

Display file or file system information

stat <file path|filesystem path>

Display ELF-file information

readelf -a <file path|filesystem path>

Show header of file

cat /usr/bin/python3.9 | hexdump -C | head

Compare files

comm
diff

Merge files

paste

Clean file

truncate -s 0 <file_name>
echo '' > <file_name>
> <file_name>
cat /dev/null > <file_name>
true | tee <file_name>
dd if=/dev/null of=<file_name>
shred <file_name>
shred -zu <file_name>

Translate or delete characters

tr

Show inodes

ls -i <file path>

Show file system where file

df <file path>

Print the locate of binary

type -a command
whereis command
which command
command -v command

Show all symbols

cat -A file_name

Find changed files use md5

find . -type f -exec md5sum {} \; > checklist.chk
md5sum -c checklist.chk

Display in hexadecimal

hexdump -C
xdd

Output starting with byte

tail -c +<number of bytes> <file name>

Display the assembler mnemonics for the machine instructions

objdump -d <file name>

Search in files

find -name *.c -type f | xargs grep open

grep -R open --include="*.c".

Ldd

Show shared object dependencies

ldd /path_to_object

TAR

Create archive

tar -cvpzf archive.tar.gz /forpack

Unpack archive

tar -xzvf archive.tar.gz
tar -xfvj archive.tar.bz2 -C /var/www

View archive

tar -tf archive.tar

TREE

tree -d -L 2

SED

Replace in all files

sed -i 's/old_text/new_text/g' *

Grep

Print only matching parts

grep -Eo "pattern" file | sort | uniq

Cp

Copy with attributes mode, ownership, timestamps

cp -rp /source /destination

Copy with save all parameters

cp -a /source /destination

Backup

cp <file name>.txt{,.bak}

Shred

Overwrite a file and delete

shred -zvu -n 10 file_name

Overwrite a file

shred -zv -n 10 file_name

Overwrite a partition

shred -fvz /dev/sdXX

Tail

Terminate tail when process over

tail -f <file name> --pid=<PID>

Wait when file exist

tail -f <file name> --retry