Större, mindre eller likamed?

man test:

s1 = s2       True if the strings s1 and s2 are identical.

     s1 != s2      True if the strings s1 and s2 are not identical.

     s1 < s2       True if string s1 comes before s2 based on the ASCII value
                   of their characters.

     s1 > s2       True if string s1 comes after s2 based on the ASCII value
                   of their characters.

Likamed och dess vänner använder man alltså bara för strängar. Det du letar efter är följande:

n1 -eq n2     True if the integers n1 and n2 are algebraically equal.

     n1 -ne n2     True if the integers n1 and n2 are not algebraically equal.

     n1 -gt n2     True if the integer n1 is algebraically greater than the
                   integer n2.

     n1 -ge n2     True if the integer n1 is algebraically greater than or
                   equal to the integer n2.

     n1 -lt n2     True if the integer n1 is algebraically less than the inte-
                   ger n2.

     n1 -le n2     True if the integer n1 is algebraically less than or equal
                   to the integer n2.

Exempel:

read varde
[ $varde -lt 10 ] && echo "mindre an 10" || echo "storre an 10"

Följande exempel kanske är lite overkill för dig. Jag använder dock denna mall hämtad ifrån OpenBSDs installationsscript när jag vill ställa frågor till användare i shellscript:

# Ask for user input.
#
#    $1    = the question to ask the user
#    $2    = the default answer
#
# Save the user input (or the default) in $resp.
ask() {
        local _question=$1 _default=$2

        set -o noglob
        while :; do
                echo -n "$_question "
                [[ -z $_default ]] || echo -n "[$_default] "
                read resp
                case $resp in
                *)        : ${resp:=$_default}
                        break
                        ;;
                esac
        done
        set +o noglob
}

# Ask the user for a y or n, and insist on 'y', 'yes', 'n' or 'no'.
#
#    $1    = the question to ask the user
#    $2    = the default answer (assumed to be 'n' if empty).
#
# Return 'yes' or 'no' in $resp.
ask_yn() {
        local _q=$1 _a=${2:-no} _resp
        typeset -l _resp

        while :; do
                ask "$_q" "$_a"
                _resp=$resp
                case $_resp in
                y|yes)        resp=yes ; return ;;
                n|no)        resp=no ; return ;;
                esac
        done
}

Funktionerna används sedan på följande sätt:

ask_yn "Do you want to commit this?"
[[ ${resp} == "no" ]] && exit

Antal tecken i en variabel

c1:~ admin$ a=Wire
c1:~ admin$ echo -n $a | wc -c
       4
c1:~ admin$