Guida avanzata di scripting Bash - Portale Posta DMI

}
Appendice A. Script aggiuntivi
s1_val=${!1} # indirect variable expansion
s2_val=${!2}
eval "$1"=\’"${s1_val}${s2_val}"\’
# ==> eval $1=’${s1_val}${s2_val}’ avoids problems,
# ==> if one of the variables contains a single quote.
#:docstring strncat:
# Usage: strncat s1 s2 $n
#
# Line strcat, but strncat appends a maximum of n characters from the value
# of variable s2. It copies fewer if the value of variabl s2 is shorter
# than n characters. Echoes result on stdout.
#
# Example:
# a=foo
# b=barbaz
# strncat a b 3
# echo $a
# => foobar
#
#:end docstring:
###;;;autoload
function strncat ()
{
local s1="$1"
local s2="$2"
local -i n="$3"
local s1_val s2_val
}
s1_val=${!s1} # ==> indirect variable expansion
s2_val=${!s2}
if [ ${#s2_val} -gt ${n} ]; then
s2_val=${s2_val:0:$n} # ==> substring extraction
fi
eval "$s1"=\’"${s1_val}${s2_val}"\’
# ==> eval $1=’${s1_val}${s2_val}’ avoids problems,
# ==> if one of the variables contains a single quote.
#:docstring strcmp:
# Usage: strcmp $s1 $s2
#
# Strcmp compares its arguments and returns an integer less than, equal to,
# or greater than zero, depending on whether string s1 is lexicographically
# less than, equal to, or greater than string s2.
#:end docstring:
###;;;autoload
function strcmp ()
640