shell text wrangling Flashcards
(32 cards)
1
Q
<
A
redirecting input
2
Q
>
A
redirecting output
3
Q
1>
A
redirecting output
4
Q
2>
A
redirecting error
5
Q
/dev/null
A
a special device file that discards all data written to it
6
Q
head
A
used to print the first n lines (default 10)
7
Q
tail
A
used to print the last n lines
8
Q
.
A
any single character
9
Q
[abc]
A
any of the characters in the brackets
10
Q
[a-z]
A
any character in the range a-z
11
Q
[^a-c]
A
means not containing a, b or c
12
Q
(a|b)
A
either a or b
13
Q
*
A
0 or more
14
Q
+
A
1 or more
15
Q
?
A
exactly 0 or 1
16
Q
{X}
A
exactly X characters of the specific kind
17
Q
{X,Y}
A
means we want X to Y characters of the specific kind
18
Q
A
start of the line
19
Q
$
A
end of the line
20
Q
sed -g
A
replaces all matches, not only the first one
21
Q
awk -F””
A
field delimiter
22
Q
~ matches
A
!~ does not match
23
Q
$0
A
whole line
24
Q
$N
A
N field
25
FS
input field separator
26
OFS
output field separator
27
NF
number of fields
28
NR
number of records(lines)
29
RS
record separator
30
ORS
output record separator
31
FILENAME
current file name
32
