File

Linux Kernel modes for file I/O: buffered and direct. (See also: kswapd and Jens Axboe)

• Basic operating commands: cp, mv, rm, touch
• truncate, fallocate, ln
• join
• Information: stat, wc
• Manipulate file content: tr, awk, sed
• Editors: vim, emacs
• cat, col, tail, more, less
• grep, ack, ag
• diff

Examples

file gdrive
gdrive: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-x86_64.so.1, not stripped

file minikube_binary
minikube_binary: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), not 
stripped

file file.img
file.img: DOS/MBR boot sector; partition 1 : ID=0xc, active, start-CHS (0x0,0,2), end-CHS (0x41,4,4), startsector 1, 1044480 sectors; partition 2 : ID=0x83, start-CHS (0x41,4,5), end-CHS (0x3e7,35,61), startsector 1044481, 31457280 sectors

file your_pem_file.pem
your_pem_file.pem PEM RSA private key

file cert.pem
cert.pem: PEM certificate

file id_rsa
id_rsa: OpenSSH private key

file private_key_file
private_key_file: OpenSSH private key

file searchindex.MYI
searchindex.MYI: MySQL MyISAM index file Version 1, 3 key parts, 0 unique key parts, 3 keys, 5734 records, 0 deleted records

file venv/bin/activate
venv/bin/activate: ASCII text

file /etc/apt/trusted.gpg
/etc/apt/trusted.gpg: GPG key public ring, created .../...

file /usr/share/keyrings/hashicorp-archive-keyring.gpg
/usr/share/keyrings/hashicorp-archive-keyring.gpg: PGP/GPG key public ring (v4) created Thu Jun  7 18:09:42 2020 RSA (Encrypt or Sign) 4096 bits MPI=0xcb4b530fed7acc95...

file your_public_key.asc 
PGP public key block Public-Key (old)

file timescaledb-tune
timescaledb-tune: Mach-O 64-bit executable x86_64

 file mariadb-bin.index
mariadb-bin.index: ASCII text

file mariadb-bin.000003
mariadb-bin.000003: MySQL replication log, server id 1 MySQL V5+, server version 10.4.21-MariaDB-1:10.4.21+maria~bionic-log

file file.tar.gz
file.tar.gz: gzip compressed data, from Unix

file /etc/mail/genericstable.db
/etc/mail/genericstable.db: Berkeley DB (Hash, version 9, native byte-order)

file text.txt
text.txt: ASCII text

Related terms

• File operations: cp, mv, rm, ln
• directory
• ulimit: ulimit -n 8192
• line
• file (command)
• dd
• Hidden files
• Ansible: file, lineinfile, blockinfile
• file (Terraform)
• Terraform provisioner file
• inode
• find . -type f
• file (Puppet)
• ASCII
• Logs
• too many open files

See also

• file, /usr/share/keyrings/, file --help
• cat, tac, more, less, tail, mtail, echo, stdin, tr, column, paste, truncate, logrotate, xzcat pv, progress, sort, ncat, virt-cat, awk, join, col, fold, tee, sponge, nfs-cat, journalctl, ccat, icat, EOF, lolcat
• file, File system, directory, touch, mkdir, ls, ln truncate, fallocate, split, stat, inode, File descriptor, superblock, block size (blockdev), fuser, lsof, scrub, chattr, ulimit (nofiles), cp, mv, file (command), mkfifo, chmod
• File systems: ext4, XFS, ZFS, btrfs, wipefs, findfs, HDFS, overlay, aufs, virt-filesystems, Windows: (FAT, NTFS, ReFS), GPFS, squashfs, Ecryptfs, Encfs, FUSE, VMFS, Comparison of distributed file systems, Userspace filesystem, Resize filesystem size