Linux and Bash tables¶

Useful cheatsheet tables for Linux and Bash.

Filesystem¶

type	in `ls`	description
regular file	`-`	real file
directory	`d`	real directory
symbolic link	`l`	pointer to another inode
character device	`c`	unbuffered device like a terminal or `/dev/null`
block device	`b`	buffered device like a disk or partition
socket	`s`	UNIX domain socket for IPC
named pipe (FIFO)	`p`	named pipe for IPC

Table 1. Inode types with associated symbols in ls -l

attribute	applies to	Description
`st_ino`	all	inode number
`st_mode`	all	type and permissions (bitmask)
`st_nlink`	all	number of hard links
`st_uid`	all	owner user ID
`st_gid`	all	owner group ID
`st_size`	file, symlink	size in bytes
`st_atime`	all	last access
`st_mtime`	all	last modification
`st_ctime`	all	last status change (e.g. owner)
`st_blksize`	all	preferred I/O block size
`st_blocks`	all	number of 512-byte blocks allocated
`st_rdev`	char device, block device	device id (major+minor)

Note

find -printf (man7 link) is not related to find.

Specifier	Meaning	Bash	C	awk
`%s`	String	✅	✅	✅
`%b`	Escapes processed string	✅	❌	❌
`%d`	Signed decimal integer	✅	✅	✅
`%i`	Signed decimal integer	✅	✅	✅
`%u`	Unsigned decimal integer	✅	✅	✅
`%x`	Unsigned hex (lowercase)	✅	✅	✅
`%X`	Unsigned hex (uppercase)	✅	✅	✅
`%o`	Unsigned octal	✅	✅	✅
`%f`	Float (fixed-point)	✅	✅	✅
`%e`	Float (scientific, lowercase)	✅	✅	✅
`%E`	Float (scientific, uppercase)	✅	✅	✅
`%g`	Float, shortest of `%f` or `%e`	✅	✅	✅
`%G`	Float, shortest of `%f` or `%E`	✅	✅	✅
`%c`	Single character	✅	✅	✅
`%p`	Pointer or path	❌	✅	✅
`%n`	Store # chars written (C only)	❌	⚠️	❌
`%%`	Literal percent sign	✅	✅	✅
`%q`	Shell-escaped string	✅	❌	❌
`%Nd`	Zero-padded to `N` chars	✅	✅	✅
`%-Ns`	Left-aligned string	✅	✅	✅

⚠️ = dangerous and should not be used