The built-in string functions are much more significant
and interesting than the numeric functions. Because awk is essentially
designed as a string-processing language, a lot of its power derives
from these functions. Table 9.2 lists the
string functions found in awk.
Table 9.2. Awk's Built-In String Functions
Awk Function
Description
gsub(r,s,t)
Globally substitutes s for
each match of the regular expression r in
the string t. Returns the number of
substitutions. If t is not supplied,
defaults to $0.
index(s,t)
Returns position of substring
t in string s or zero
if not present.
length(s)
Returns length of string s or
length of $0 if no string is
supplied.
match(s,r)
Returns either the position in
s where the regular expression
r begins, or 0 if no occurrences are found.
Sets the values of RSTART and
RLENGTH.
split(s,a,sep)
Parses string s into elements
of array a using field separator
sep; returns number of elements. If
sep is not supplied, FS is used. Array splitting works the
same way as field splitting.
sprintf("fmt",expr)
Uses printf format
specification for expr.
sub(r,s,t)
Substitutes s for first match
of the regular expression r in the string
t. Returns 1 if successful; 0 otherwise. If
t is not supplied, defaults to $0.
substr(s,p,n)
Returns substring of string s
at beginning position p up to a maximum
length of n. If n is
not supplied, the rest of the string from p
is used.
tolower(s)
Translates all uppercase characters in string
s to lowercase and returns the new string.
toupper(s)
Translates all lowercase characters in string
s to uppercase and returns the new string.
You are currently reading a PREVIEW of this book.
Get instant access to over
$1 million worth of books and videos.
