Bash Shell Quick Reference

Written by Aurelio Jargas on July 06, 2011

Note: This document was translated from portuguese to english by Luiz Miguel Axcar.

1. Operators

Arithmetic Operators
`+`	Addition
`-`	Subtraction
`*`	Multiplication
`/`	Division
`%`	Modulo
`**`	Exponentiation
Attribution Operators
`=`	Attribute some value to a variable
`+=`	Increase a variable with a constant
`-=`	Decrease a variable with a constant
`*=`	Multiply the variable by a constant
`/=`	Divide a variable by a constant
`%=`	Remainder of division by a constant
`++`	Increase 1 to the variable value
`--`	Decrease 1 from the variable value
Comparison Operators
`==`	Equals
`!=`	Not equals to (different)
`>`	Greater than
`>=`	Greater than or equal to
`<`	Less than
`<=`	Less than or equal to
Logical Operators
`&&`	Logical AND
`\|\|`	Logical OR
Bitwise Operators
`<<`	Left-shift
`>>`	Right-shift
`&`	Bitwise AND
`\|`	Bitwise OR
`^`	Bitwise Exclusive OR (XOR)
`~`	Bitwise NOT (complement)
`!`	NOT
Bitwise Operators (attribution)
`<<=`	Left-shift
`>>=`	Right-shift
`&=`	Bitwise AND
`\|=`	Bitwise OR
`^=`	Bitwise Exclusive OR (XOR)

2. Redirection

Operator	Action
`<`	Redirect the standard input (STDIN)
`>`	Redirect the standard output (STDOUT)
`2>`	Redirect the error output (STDERR)
`>>`	Redirect the standard output, appending
`2>>`	Redirect the error output, appending
`\|`	Connects the standard output with standard input of another command
`2>&1`	Connects the error output with standard output
`>&2`	Connects the standard output with error output
`>&-`	Closes the standard output
`2>&-`	Closes the error output
`3<>file`	Connects the file descriptor 3 to file 'file'
`<<FIM`	Feeds the standard input (Here Document)
`<<-FIM`	Feeds the standard input, striping TABs
`<(cmd)`	The output of command 'cmd' is a file: diff <(cmd1) <(cmd2)
`>(cmd)`	The input of command 'cmd' is a file: tar cf >(bzip2 -c >file.tbz) $dir

3. Special variables

Variable	Positioning parameters
`$0`	Parameter #0 (name of command or function)
`$1`	Parameter #1 (from command line or function)
`...`	Parameter #N ...
`$9`	Parameter #9 (from command line or function)
`${10}`	Parameter #10 (from command line or function)
`...`	Parameter #NN ...
`$#`	Total number of parameters from command line or function
`$*`	All the parameters, in a single string
`$@`	All the parameters, in many protected strings
Variable	Misc
`$$`	PID of current process (or script)
`$!`	PID of last job in background
`$_`	Last argument of last executed command
`$?`	Error code of last executed command

4. Variable expansion

Syntax	Conditional Expansion
`${var:-text}`	If var is undefined, returns 'text'
`${var:=text}`	If var is undefined, set as 'text'
`${var:?text}`	If var is undefined, returns error message 'text'
`${var:+text}`	If var is defined, returns 'text', else return empty
Syntax	String expansion
`${var}`	Is the same of $var, but not ambiguous
`${#var}`	Return the string length
`${!var}`	Executes the content of $var (like 'eval \$$var')
`${!text*}`	Return the names of variables starting with 'text'
`${var:N}`	Return the text from position 'N'
`${var:N:len}`	Return 'len' chars from position 'N'
`${var#text}`	Cut 'text' from beginning of string
`${var##text}`	Cut 'text' from beginning of string (*greedy)
`${var%text}`	Cut 'text' from end of string
`${var%%text}`	Cut 'text' from end of string (*greedy)
`${var/text/new}`	Replace 'text' by 'new', once
`${var//text/new}`	Replace 'text' by 'new', all
`${var/#text/new}`	If string starts with 'text', replace 'text' by 'new'
`${var/%text/new}`	If string ends with 'text', replace 'text' by 'new'
`${var^}`	Uppercase the first character
`${var^^}`	Uppercase all the characters
`${var,}`	Lowercase the first character
`${var,,}`	Lowercase all the characters
`${var~}`	Reverse the case of the first character
`${var~~}`	Reverse the case of all the characters

5. Quoting and grouping

Syntax	Description	Example
`"..."`	Protects a string, but parse $, \ and ` as special chars	"abc"
`'...'`	Protects a string completely (no special chars recognized)	'abc'
`$'...'`	Protects a string completely, but interprets \n, \t, \a, etc	$'abc\n'
`...`	Execute commands in a subshell, returning the result	`ls`
`{...}`	Group commands	{ ls ; }
`(...)`	Execute commands in a subshell	( ls )
`$(...)`	Execute commands in a subshell, returning the result	$( ls )
`((...))`	Test an arithmetic operation, returning 0 or 1	((5 > 3))
`$((...))`	Return the result of a arithmetic operation	$((5+3))
`[...]`	Test an arithmetic expression, returning 0 or 1 (alias of command 'test')	[ 5 -gt 3 ]
`[[...]]`	Test an expression, returning 0 or 1 (&& and \|\| are allowed)	[[ 5 > 3 ]]

6. if, for, select, while, until, case

if	for / select
if COMMAND then ... elif COMMAND then ... else ... fi	for VAR in LIST do ... done or: for ((exp1;exp2;exp3))
while / until	case
while COMMAND do ... done	case $VAR in txt1) ... ;; txt2) ... ;; txtN) ... ;; *) ... ;; esac

7. test or [ … ]

Numeric comparison
`-lt`	Less Than
`-gt`	Greater than
`-le`	Less than or Equal to
`-ge`	Greater than or Equal to
`-eq`	Equals
`-ne`	Not Equal to (different)
String comparison
`=`	Equals
`!=`	Not Equal to (different)
`-n`	Not NULL
`-z`	Is NULL
Logical Operators
`!`	Logical NOT
`-a`	Logical AND
`-o`	Logical OR
Testing files
`-b`	Is a block device
`-c`	Is a char device
`-d`	Is a directory
`-e`	File exists
`-f`	Is a regular file
`-g`	SGID bit is switched on
`-G`	Current user is in the file's group
`-k`	Sticky-bit is switched on
`-L`	File is a symlink
`-O`	Current user owns the file
`-p`	File is a named pipe
`-r`	File has read permission
`-s`	File size is greater than zero
`-S`	File is a socket
`-t`	File descriptor N is a terminal
`-u`	SUID bit is switched on
`-w`	File has write permission
`-x`	File has execution permission
`-nt`	File is Newer Than
`-ot`	File is Older Than
`-ef`	File is the same - Equal File

8. Prompt escapes ($PS1)

Escape	Reminder	Expands to...
\a	Alert	Alert (beep)
\d	Date	Date in format "Week-day Month Day" (Sat Jan 15)
\e	Escape	Esc character
\h	Hostname	Hostname without the domain (dhcp11)
\H	Hostname	Full hostname (dhcp11.company)
\j	Jobs	Number of active jobs
\l	Tty	Name of current terminal (ttyp1)
\n	Newline	New Line
\r	Return	Carriage return
\s	Shell	Shell name (basename $0)
\t	Time	Time in 24 hours format HH:MM:SS
\T	Time	Time in 12 hours format HH:MM:SS
\@	At	Time in 12 hours format HH:MM am/pm
\A	At	Time in 24 hours format HH:MM
\u	User	Current user login
\v	Version	Bash Version (2.00)
\V	Version	Bash Version + Subversion (2.00.0)
\w	Working Dir	Full working dir ($PWD)
\W	Working Dir	Last working dir (basename $PWD)
\!	History	Number of current command in history
\#	Number	Number of current command
\$	ID	Show "#" if user is root, and "$" in case of a regular user
\nnn	Octal	Char which Octal value is nnn
\\	Backslash	Backslash \ literal
\[	Escapes	Start a escape sequence (color codes)
\]	Escapes	Finish a escape sequence

9. echo escapes

Escape	Reminder	Description
\a	Alert	Alert (beep)
\b	Backspace	Backspace character
\c	EOS	Ends the string
\e	Escape	Esc character
\f	Form feed	Form Feed
\n	Newline	Newline
\r	Return	Carriage Return
\t	Tab	Tab
\v	Vtab	Vertical Tab
\\	Backslash	Backslash
\nnn	Octal	Character whose octal code is nn
\xnn	Hexa	Character whose hexadecimal code is nn

10. date tokens

Format	Description
`%a`	Day of the week - abbreviated name (Sun..Sat)
`%A`	Day of the week - full name (Sunday..Saturday)
`%b`	Month name - abbreviated (Jan..Dec)
`%B`	Month name - full (January..December)
`%c`	Locale's date and time (Thu 05 May 2011 11:41:41 AM EST)
`%y`	Year (two digits)
`%Y`	Year (four digits)
`%m`	Month (01..12)
`%d`	Day (01..31)
`%j`	Day of year (001..366)
`%H`	Hours (00..23)
`%M`	Minutes (00..59)
`%S`	Seconds (00..60)
`%s`	Seconds since 00:00:00, Jan 1, 1970 (Unix time)
`%%`	A literal %
`%t`	A TAB
`%n`	A newline

11. printf tokens

Format	Description
`%d`	Integer number
`%o`	Octal number
`%x`	Hexadecimal Number (a-f)
`%X`	Hexadecimal Number (A-F)
`%f`	Float number
`%e`	Scientific notation x.xxxx e nnn. float, double (e+1)
`%E`	Same as %e, but with an upper-case E in the printed format
`%s`	String

12. ls -l file identifiers

Letter	Reminder	File types (First char)
-	-	Regular file
d	Directory	Directory
l	Link	Symbolic link
b	Block	Block Device (Hard drives)
c	Char	Character device (serial modem)
s	Socket	Mapped socket in a file (processes communication)
p	Pipe	FIFO or Named Pipe (processes communication)
Letter	Reminder	File permission (next nine chars)
-	-	Deactivated
r	Read	Read Permission
w	Write	Write permission
x	eXecute	Execution permission (or directory access)
X	eXecute	Directory access only
s	Set ID	User/group for execution (SUID, SGID) - permission 'x' activated
S	Set ID	User/group for execution (SUID, SGID) - permission 'x' deactivated
t	sTicky	Users delete his own files only - permission 'x' activated
T	sTicky	Users delete his own files only - permission 'x' deactivated

13. Filenames wildcards (glob)

Wildcard	Matches...	Example
`*`	Anything	`*.txt`
`?`	Any char	`file-??.zip`
`[...]`	Any char in the group	`[Ff]ile.txt`
`[^...]`	Any char, except those in the group	`[^A-Z]*.txt`
`{...}`	Any text, comma separated	`file.{txt,html}`

14. case wildcards

Wildcard	Matches...	Example
`*`	Anything	`*.txt) echo ;;`
`?`	Any char	`file-??.zip) echo ;;`
`[...]`	Any char in the group	`[0-9]) echo ;;`
`[^...]`	Any char, except those in the group	`[^0-9]) echo ;;`
`...\|...`	Ant text, pipe separated	`txt\|html) echo ;;`

15. trap/kill/killall signals

#	Linux	Cygwin	SystemV	AIX	HP-UX	Solaris	BSD/Mac
1	HUP	HUP	HUP	HUP	HUP	HUP	HUP
2	INT	INT	INT	INT	INT	INT	INT
3	QUIT	QUIT	QUIT	QUIT	QUIT	QUIT	QUIT
4	ILL	ILL	ILL	ILL	ILL	ILL	ILL
5	TRAP	TRAP	TRAP	TRAP	TRAP	TRAP	TRAP
6	ABRT	ABRT	IOT	LOST	ABRT	ABRT	ABRT
7	BUS	EMT	EMT	EMT	EMT	EMT	EMT
8	FPE	FPE	FPE	FPE	FPE	FPE	FPE
9	KILL	KILL	KILL	KILL	KILL	KILL	KILL
10	USR1	BUS	BUS	BUS	BUS	BUS	BUS
11	SEGV	SEGV	SEGV	SEGV	SEGV	SEGV	SEGV
12	USR2	SYS	SYS	SYS	SYS	SYS	SYS
#	Linux	Cygwin	SystemV	AIX	HP-UX	Solaris	BSD/Mac
13	PIPE	PIPE	PIPE	PIPE	PIPE	PIPE	PIPE
14	ALRM	ALRM	ALRM	ALRM	ALRM	ALRM	ALRM
15	TERM	TERM	TERM	TERM	TERM	TERM	TERM
16	-	URG	USR1	URG	USR1	USR1	URG
17	CHLD	STOP	USR2	STOP	USR2	USR2	STOP
18	CONT	TSTP	CHLD	TSTP	CHLD	CHLD	TSTP
19	STOP	CONT	PWR	CONT	PWR	PWR	CONT
20	TSTP	CHLD	WINCH	CHLD	VTALRM	WINCH	CHLD
21	TTIN	TTIN	URG	TTIN	PROF	URG	TTIN
22	TTOU	TTOU	IO	TTOU	IO	IO	TTOU
23	URG	IO	STOP	IO	WINCH	STOP	IO
24	XCPU	XCPU	TSTP	XCPU	STOP	TSTP	XCPU
#	Linux	Cygwin	SystemV	AIX	HP-UX	Solaris	BSD/Mac
25	XFSZ	XFSZ	CONT	XFSZ	TSTP	CONT	XFSZ
26	VTALRM	VTALRM	TTIN	-	CONT	TTIN	VTALRM
27	PROF	PROF	TTOU	MSG	TTIN	TTOU	PROF
28	WINCH	WINCH	VTALRM	WINCH	TTOU	VTALRM	WINCH
29	IO	LOST	PROF	PWR	URG	PROF	INFO
30	PWR	USR1	XCPU	USR1	LOST	XCPU	USR1
31	SYS	USR2	XFSZ	USR2	-	XFSZ	USR2
32	-	-	-	PROF	-	WAITING	-
33	-	-	-	DANGER	-	LWP	-
34	-	-	-	VTALRM	-	FREEZE	-
35	-	-	-	MIGRATE	-	THAW	-
36	-	-	-	PRE	-	CANCEL	-
37	-	-	-	-	-	LOST	-

How you can get this list: trap -l, kill -l or killall -l
See also: man 7 signal

16. Exit codes

Code	Meaning	Example
0	No errors	echo
1	Catchall for most common errors	echo $((1/0))
2	Misuse of shell builtins	-
126	Command cannot be executed (no permission)	touch a ; ./a
127	Command not found	echooo
128	Invalid argument to exit	exit 1.0
128+n	128 + exit code which was killed	kill -9 $PPID #exit 137
130	Script terminated by Ctrl+C (128 + 2)	-
255	'exit' parameter not between 0 and 255	exit -1

17. Color codes (ANSI)

Color	Letter	Background
Black	30	40
Red	31	41
Green	32	42
Yellow	33	43
Blue	34	44
Pink	35	45
Cyan	36	46
White	37	47
Attribute		Value
Reset		0
Bold		1
Underline		4
Blinking		5
Reverse		7
Examples: ESC [ <N>;<N> m
Regular text (Turn color off)		`ESC[m`
Bold		`ESC[1m`
Yellow		`ESC[33;1m`
Blue background, gray letter		`ESC[44;37m`
Blinking red		`ESC[31;5m`
On the command line
`echo -e '\e[33;1m yellow \e[m'`
`echo -e '\033[33;1m yellow \033[m'`

18. Regex metacharacters

Meta	Name	Description
.	Dot	Matches exactly one char (any char)
[]	List	Matches any char in the group
[^]	Negated list	Matches any char, except those in the group
?	Optional	Matches the preceding item zero or one time
*	Star	Matches the preceding item zero or more times
+	Plus	Matches the preceding item one or more times
{,}	Repeat	Matches the preceding item between m and n times {m,n}
^	Caret	Matches the start of the line
$	Dollar	Matches the end of the line
\b	Boundary	Matches the word boundary
\	Escape	Escapes a metacharacter, taking off its power
\|	OR	Alternatives (use inside a group)
()	Group	Group slices of expression, nesting is allowed
\1	Backreference	Returns group #1 contents
\2	Backreference	Returns group #2 contents (until \9)
.*	Catchall	Matches everything, even nothing
??	Lazy Optional	Like regular Optional, but not greedy
*?	Lazy Star	Like regular Star, but not greedy
+?	Lazy Plus	Like regular Plus, but not greedy
{}?	Lazy Repeat	Like regular Repeat, but not greedy

19. Regex flavors

Program	Opt	Plus	Repeat	Boundary	OR	Group
awk	?	+	-	-	\|	()
ed	\?	\+	\{,\}	\b	\\|
egrep	?	+	{,}	\b	\|	()
emacs	?	+	-	\b	\\|
expect	?	+	-	-	\|	()
find	?	+	-	\b	\\|
gawk	?	+	{,}	\<\>	\|	()
grep	\?	\+	\{,\}	\b	\\|
mawk	?	+	-	-	\|	()
perl	?	+	{,}	\b	\|	()
php	?	+	{,}	\b	\|	()
python	?	+	{,}	\b	\|	()
sed	\?	\+	\{,\}	\<\>	\\|
vim	\=	\+	\{,}	\<\>	\\|

20. Printable ASCII characters (ISO-8859-1) - text

32        64  @     96  `    162  ¢    194  Â    226  â
33  !     65  A     97  a    163  £    195  Ã    227  ã
34  "     66  B     98  b    164  ¤    196  Ä    228  ä
35  #     67  C     99  c    165  ¥    197  Å    229  å
36  $     68  D    100  d    166  ¦    198  Æ    230  æ
37  %     69  E    101  e    167  §    199  Ç    231  ç
38  &     70  F    102  f    168  ¨    200  È    232  è
39  '     71  G    103  g    169  ©    201  É    233  é
40  (     72  H    104  h    170  ª    202  Ê    234  ê
41  )     73  I    105  i    171  «    203  Ë    235  ë
42  *     74  J    106  j    172  ¬    204  Ì    236  ì
43  +     75  K    107  k    173       205  Í    237  í
44  ,     76  L    108  l    174  ®    206  Î    238  î
45  -     77  M    109  m    175  ¯    207  Ï    239  ï
46  .     78  N    110  n    176  °    208  Ð    240  ð
47  /     79  O    111  o    177  ±    209  Ñ    241  ñ
48  0     80  P    112  p    178  ²    210  Ò    242  ò
49  1     81  Q    113  q    179  ³    211  Ó    243  ó
50  2     82  R    114  r    180  ´    212  Ô    244  ô
51  3     83  S    115  s    181  µ    213  Õ    245  õ
52  4     84  T    116  t    182  ¶    214  Ö    246  ö
53  5     85  U    117  u    183  ·    215  ×    247  ÷
54  6     86  V    118  v    184  ¸    216  Ø    248  ø
55  7     87  W    119  w    185  ¹    217  Ù    249  ù
56  8     88  X    120  x    186  º    218  Ú    250  ú
57  9     89  Y    121  y    187  »    219  Û    251  û
58  :     90  Z    122  z    188  ¼    220  Ü    252  ü
59  ;     91  [    123  {    189  ½    221  Ý    253  ý
60  <     92  \    124  |    190  ¾    222  Þ    254  þ
61  =     93  ]    125  }    191  ¿    223  ß    255  ÿ
62  >     94  ^    126  ~    192  À    224  à
63  ?     95  _    161  ¡    193  Á    225  á

21. Printable ASCII characters (ISO-8859-1) - image

22. Copy-paste friendly commands

Conditions with IF
`if [ -f "$file" ]; then echo 'File found'; fi`
`if [ ! -d "$dir" ]; then echo 'Directory not found'; fi`
`if [ $i -gt 5 ]; then echo 'Greater than 5'; else echo 'Lesser than 5'; fi`
`if [ $i -ge 5 -a $i -le 10 ]; then echo 'Between 5 and 10, inclusive'; fi`
`if [ $i -eq 5 ]; then echo '=5'; elif [ $i -gt 5 ]; then echo '>5'; else echo '<5'; fi`
`if [ "$USER" = 'root' ]; then echo 'Hello root'; fi`
`if grep -qs 'root' /etc/passwd; then echo 'User found'; fi`
Conditions with AND (&&) and OR (\|\|)
`[ -f "$file" ] && echo 'File found'`
`[ -d "$dir" ] \|\| echo 'Directory not found'`
`grep -qs 'root' /etc/passwd && echo 'User found'`
`cd "$dir" && rm "$file" && touch "$file" && echo 'done!'`
`[ "$1" ] && param=$1 \|\| param='default value'`
`[ "$1" ] && param=${1:-default value}`
`[ "$1" ] \|\| { echo "Usage: $0 parameter" ; exit 1 ; }`
Adds 1 to variable $i
`i=$(expr $i + 1)`
`i=$((i+1))`
`let i=i+1`
`let i+=1`
`let i++`
Loop from 1 to 10
`for i in 1 2 3 4 5 6 7 8 9 10; do echo $i; done`
`for i in $(seq 10); do echo $i; done`
`for ((i=1;i<=10;i++)); do echo $i; done`
`i=1 ; while [ $i -le 10 ]; do echo $i ; i=$((i+1)) ; done`
`i=1 ; until [ $i -gt 10 ]; do echo $i ; i=$((i+1)) ; done`
Loop reading lines from a file or command output
`cat /etc/passwd \| while read LINE; do echo "$LINE"; done`
`grep 'root' /etc/passwd \| while read LINE; do echo "$LINE"; done`
`while read LINE; do echo "$LINE"; done < /etc/passwd`
`while read LINE; do echo "$LINE"; done < <(grep 'root' /etc/passwd)`
Wildcards for case command
`case "$dir" in /home/*) echo 'dir inside /home';; esac`
`case "$user" in root\|john\|mary) echo "Hello $user";; *) echo "I don't know you.";; esac`
`case "$var" in ?) echo '1 letter';; ??) echo '2 letters';; ??*) echo 'More than 2 letters';; esac`
`case "$i" in [0-9]) echo '1 digit';; [0-9][0-9]) echo '2 digits';; esac`
Dialog boxes
`dialog --calendar 'abc' 0 0 31 12 1999`
`dialog --checklist 'abc' 0 0 0 item1 'desc1' on item2 'desc2' off`
`dialog --fselect /tmp 0 0`
`(echo 50; sleep 2; echo 100) \| dialog --gauge 'abc' 8 40 0`
`dialog --infobox 'abc' 0 0`
`dialog --inputbox 'abc' 0 0`
`dialog --passwordbox 'abc' 0 0`
`dialog --menu 'abc' 0 0 0 item1 'desc1' item2 'desc2'`
`dialog --msgbox 'abc' 8 40`
`dialog --radiolist 'abc' 0 0 0 item1 'desc1' on item2 'desc2' off`
`dialog --tailbox /tmp/file.txt 0 0`
`dialog --textbox /tmp/file.txt 0 0`
`dialog --timebox 'abc' 0 0 23 59 00`
`dialog --yesno 'abc' 0 0`
Hint 1: `Dialog ... && echo 'You pressed OK/Yes' \|\| echo 'You pressed Cancel/No'`
Hint 2: `result=$(Dialog --stdout --BOXTYPE 'abc' ...)`

23. Command line shortcuts (set -o emacs)

Shortcut	Description	Similar key
Ctrl+A	Move the cursor to the beginning of line	Home
Ctrl+B	Move the cursor one position left	←
Ctrl+C	Send EOF() to the system
Ctrl+D	Delete the char at right	Delete
Ctrl+E	Move the cursor to the end of line	End
Ctrl+F	Move the cursor one position at right	→
Ctrl+H	Delete the char at left	Backspace
Ctrl+I	Complete files and commands	Tab
Ctrl+J	Line break	Enter
Ctrl+K	Cut from cursor to the end of line
Ctrl+L	Clear screen
Ctrl+N	Next command
Ctrl+P	Previous command
Ctrl+Q	Unlock the shell (see Ctrl+S)
Ctrl+R	Seek in the command history
Ctrl+S	Lock the shell (see Ctrl+Q)
Ctrl+T	Exchange two chars position
Ctrl+U	Cut the whole line
Ctrl+V	Insert a literal character
Ctrl+W	Cut word at left
Ctrl+X	Move the cursor to end/beginning of line (2x)	Home/End
Ctrl+Y	Paste the text

24. Toolbox

Command	Function	Useful options
cat	Show file contents	-n, -s
cut	Extract fields	-d -f, -c
date	Show date	-d, +'...'
diff	Compare files	-u, -Nr, -i, -w
echo	Show text	-e, -n
find	Find files	-name, -iname, -type f, -exec, -or
fmt	Format paragraph	-w, -u
grep	Search for text	-i, -v, -r, -qs, -n, -l, -w -x, -A -B -C
head	Show first lines	-n, -c
od	Show chars	-a, -c, -o, -x
paste	Merge files	-d, -s
printf	Show text	nothing
rev	Reverse text	nothing
sed	Edit text	-n, -f, s/this/that/, p, d, q, N
seq	Count numbers	-s, -f
sort	Sort text	-n, -f, -r, -k -t, -o
tac	Reverse file	nothing
tail	Show last lines	-n, -c, -f
tee	Save the stream	-a
tr	Transforms the text	-d, -s, A-Z a-z
uniq	Remove duplicated	-i, -d, -u
wc	Count letters	-c, -w, -l, -L
xargs	Manage arguments	-n, -i

— EOF —

Program	Opt	Plus	Repeat	Boundary	OR	Group
awk	?	+	-	-	\|	()
ed	\?	\+	\{,\}	\b	\\|	\(\)
egrep	?	+	{,}	\b	\|	()
emacs	?	+	-	\b	\\|	\(\)
expect	?	+	-	-	\|	()
find	?	+	-	\b	\\|	\(\)
gawk	?	+	{,}	\<\>	\|	()
grep	\?	\+	\{,\}	\b	\\|	\(\)
mawk	?	+	-	-	\|	()
perl	?	+	{,}	\b	\|	()
php	?	+	{,}	\b	\|	()
python	?	+	{,}	\b	\|	()
sed	\?	\+	\{,\}	\<\>	\\|	\(\)
vim	\=	\+	\{,}	\<\>	\\|	\(\)