Working with the Unix OS

Unix Tools
BEGIN ( FS="\t" }
{ $4 = 1000 * $3 / $2; print}
# string concatenation
/A/ { s = s" "$1 }
END { print s }
# arrays
{ x[NR] = $0 }
END { ... program ...}
! Special Features
Built-in Functions
# print length of line
{ print length $0 }
# print country with longest name
length($1) > max { max = length($1); name = $1 }
END { print name }
# abbreviate country names to 3 letters
{ $1 = substr($1, 1, 3); print }
Flow of Control
{ if (maxpop < $3)
{
maxpop = $3
country = $1
}
}
END { print country, maxpop }
{ i = 1
while (i