First note that unlike C functions, shell functions can't return negative values. (The exit code from a shell function is a value in the range 0 through 255, inclusive.) Looking at your original script, it uses only two return values: 0 and 77. However, I don't know what the calls to fail do in your script. If they exit, that would exit the shell script that calls your function instead of just returning an error code for your function.
The following replacement for your function assumes that fail is a function that prints a diagnostic message and returns to the caller. (So after calling fail, this version of your function returns a non-zero exit status indicating that the checkversion() function was not able to successfully compare to version strings.) If this version of checkversion() does successfully compare two version strings it returns 0 and sets the variable checkversion_result to an integral value that is zero if the versions are the same, a value greater than zero if the version found in the symbolic link identified by the 1st operand is greater than the version passed in as the 2nd operand, or a value less than zero if the version found in the symlink is less than the version given as the 2nd operand.
All of the command substitutions using cut to find various subfields have been replaced by parameter substitutions (so this should be considerably faster). Debugging printf statements have been added so you can see each test being performed and the values used to determine the final result that is returned. (If the code is giving you values that are appropriate for what you're trying to do, you can remove all of the printf statements that start at the left margin. Note that I am not at all sure that I have the results correct in one, and only one, of the version strings contains RC_.)
This should all work with any shell that performs the parameter expansions required by the POSIX standards. (It has been tested with bash and ksh.) Like your script, it will only work on a system that includes a readlink utility. (The readlink utility is provided by many systems, but is not required by the POSIX standards.)
Code:
checkversion_result=
checkversion() {
checkversion_result=
local mod="$1"
local vers="$2"
local slink="/app/mes_dwh/$mod/${mod}"
local target=$(readlink "$slink")
target=${target#*V}
target=V${target%%V*}
case "$target" in
(V_[0-9]_[0-9]_[0-9]_RC_b* | V_[0-9]_[0-9]_[0-9]_b*)
;;
(*) fail "bad version string: '$target'"
return 1
;;
esac
case "${target##*b}" in
(*[!0-9]*)
fail "bad build number: '$target'"
return 2
;;
esac
#compare major version
local old=${target#*_}
old=${old%%_*}
local new=${vers#*_}
new=${new%%_*}
checkversion_result=$((old - new))
printf 'major old:%s new:%s result:%s\n' "$old" "$new" "$checkversion_result"
[ "$checkversion_result" -ne 0 ] && return 0
#compare middle version
old=${target#*_*_}
old=${old%%_*}
new=${vers#*_*_}
new=${new%%_*}
checkversion_result=$((old - new))
printf 'middle old:%s new:%s result:%s\n' "$old" "$new" "$checkversion_result"
[ "$checkversion_result" -ne 0 ] && return 0
#compare minor version
old=${target#*_*_*_}
old=${old%%_*}
new=${vers#*_*_*_}
new=${new%%_*}
checkversion_result=$((old - new))
printf 'minor old:%s new:%s result:%s\n' "$old" "$new" "$checkversion_result"
[ "$checkversion_result" -ne 0 ] && return 0
#ocmpare RC_b versus b
old=${target#*_*_*_*_}
old=${old%%b*}
new=${vers#*_*_*_*_}
new=${new%%b*}
if [ "$old" != "$new" ]
then [ "$old" = "" ] && checkversion_result=1 || \
checkversion_result=-1
fi
printf 'RC old:%s new:%s result:%s\n' "$old" "$new" "$checkversion_result"
[ "$checkversion_result" -ne 0 ] && return 0
#compare build version
old=${target##*b}
new=${vers##*b}
checkversion_result=$((old - new))
printf 'build old:%s new:%s result:%s\n' "$old" "$new" "$checkversion_result"
return 0
}
The way to use this function would be something like:
Code:
if checkversion modversion
then echo "version check completed successfully, result: $checkversion_result"
else echo "version check failed; see diagnostics above"
fi
Location: Saint Paul, MN USA / BSD, CentOS, Debian, OS X, Solaris
Posts: 2,288
Thanks Given: 430
Thanked 480 Times in 395 Posts
Hi.
Here is an adaptation of a code from stackoverflow . It has a debugger so that you can see details of each sub-comparison, so it's really a verbose option that you can change in the code. I would probably do it a little differently, but this code is already completed and works as shown below:
Code:
#!/usr/bin/env bash
# @(#) s2 Demonstrate version strings comparison.
LC_ALL=C ; LANG=C ; export LC_ALL LANG
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C
FILE=${1-data1}
pl " Input data file $FILE:"
head $FILE
pl " Version comparison script:"
cat vercomp
# Compare, look at exit status.
# return 1 for $1 > $2
# return 2 for $1 < $2
# return 0 for equal
pl " Results:"
while read v1 v2
do
./vercomp "$v1" "$v2"
v0=$?
case $v0 in
(0) pe " Versions $v1 and $v2 are the equal." ;;
(1) pe " $v1 is more recent than $v2." ;;
(2) pe " $v2 is more recent than $v1." ;;
(*) pe " Internal error." ;;
esac
done < $FILE
exit 0
producing:
Code:
$ ./s2
Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 3.16.0-4-amd64, x86_64
Distribution : Debian 8.4 (jessie)
bash GNU bash 4.3.30
-----
Input data file data1:
V_1_4_4_b1 V_1_5_1_RC_b1
1.2-r3 1.2-r4
1.2rc3 1.2r4
3.14a 3.14b
-----
Version comparison script:
#!/usr/bin/env bash
# @(#) vercomp Compare version strings.
# Adapted from:
# http://stackoverflow.com/questions/4023830/bash-how-compare-two-strings-in-version-format
ascii_frag() {
expr match "$1" "\([^[:digit:]]*\)"
}
ascii_remainder() {
expr match "$1" "[^[:digit:]]*\(.*\)"
}
numeric_frag() {
expr match "$1" "\([[:digit:]]*\)"
}
numeric_remainder() {
expr match "$1" "[[:digit:]]*\(.*\)"
}
# Disable/enable debugging here.
vercomp_debug() {
OUT="$1"
# echo "${OUT}" >&2
}
# return 1 for $1 > $2
# return 2 for $1 < $2
# return 0 for equal
vercomp() {
local WORK1="$1"
local WORK2="$2"
local NUM1="", NUM2="", ASCII1="", ASCII2=""
while true; do
vercomp_debug "ASCII compare"
ASCII1=`ascii_frag "${WORK1}"`
ASCII2=`ascii_frag "${WORK2}"`
WORK1=`ascii_remainder "${WORK1}"`
WORK2=`ascii_remainder "${WORK2}"`
vercomp_debug "\"${ASCII1}\" remainder \"${WORK1}\""
vercomp_debug "\"${ASCII2}\" remainder \"${WORK2}\""
if [ "${ASCII1}" \> "${ASCII2}" ]; then
vercomp_debug "ascii ${ASCII1} > ${ASCII2}"
return 1
elif [ "${ASCII1}" \< "${ASCII2}" ]; then
vercomp_debug "ascii ${ASCII1} < ${ASCII2}"
return 2
fi
vercomp_debug "--------"
vercomp_debug "Numeric compare"
NUM1=`numeric_frag "${WORK1}"`
NUM2=`numeric_frag "${WORK2}"`
WORK1=`numeric_remainder "${WORK1}"`
WORK2=`numeric_remainder "${WORK2}"`
vercomp_debug "\"${NUM1}\" remainder \"${WORK1}\""
vercomp_debug "\"${NUM2}\" remainder \"${WORK2}\""
if [ -z "${NUM1}" -a -z "${NUM2}" ]; then
vercomp_debug "blank 1 and blank 2 equal"
return 0
elif [ -z "${NUM1}" -a -n "${NUM2}" ]; then
vercomp_debug "blank 1 less than non-blank 2"
return 2
elif [ -n "${NUM1}" -a -z "${NUM2}" ]; then
vercomp_debug "non-blank 1 greater than blank 2"
return 1
fi
if [ "${NUM1}" -gt "${NUM2}" ]; then
vercomp_debug "num ${NUM1} > ${NUM2}"
return 1
elif [ "${NUM1}" -lt "${NUM2}" ]; then
vercomp_debug "num ${NUM1} < ${NUM2}"
return 2
fi
vercomp_debug "--------"
done
}
vercomp "$@"
-----
Results:
V_1_5_1_RC_b1 is more recent than V_1_4_4_b1.
1.2-r4 is more recent than 1.2-r3.
1.2rc3 is more recent than 1.2r4.
3.14b is more recent than 3.14a.
I tested it as shown, which is not extensively, only to see if it seems to basically work.
I think there is a way to detect mouse movement.
valuator changes if the mouse moves.
So I need to compare the two strings.
Not sure how to do that.
How could I send the valuator string to a file ?
I would need to do it twice.
andy@7_~/Downloads$ xinput query-state 9
2 classes :... (7 Replies)
Hi,
I am trying to do the following to see if "ip" is already present in a file.
if ; then
echo "hi"
else
echo "hello"
fi
I am seeing errors on the if statement. Can someone please correct the syntax for me? Thanks (2 Replies)
hello guyzz
please help me out..
I have two file a.sh and b.sh it contains two string SD109 ,SD108 .
I want to compaere these two string .
If a.sh>b.sh
do rebasing
record time.
else it shows no rebasing required.
Thanks. (2 Replies)
hi..
i have a problem to compare two string
my code is like that
if ]
then
echo "both data are correct"
elif ]
echo "data is wrong"
fi
here $username1 is taking value from file.. (7 Replies)
Hello , I want to Compare with 2 strings and get if they are True or not
please would like some help on this
#!bin/ksh
echo "Enter Name 1"
read Name1
echo "Enter Name 2"
read Name2
echo "------------------------"
echo "First Name: $Name1"
echo "Second Name: $Name2"
echo... (25 Replies)
Hi Im trying to write a script that compare a text string.
But it fails, I think it adds a extra line feed to the result and fails beacuse of that.
The script.
DT=`date +'%Y%m%d%H%M%S'`
#ALARM_BIN=/users/alarms/ssa/alarms/bin
QUEUE_THR=10
#unset offset
#offset="***Server reports data... (3 Replies)
Hi,
Here is my script
#!/bin/ksh
echo $pick_typ
if ];then
echo "inside if"
else
echo "outside if"
fi
when ever i pass CUS as parameter to this script am getting the correct value CUS, however if i pass ORD as parameter it is not coming inside if it is echoing else "Outside... (12 Replies)
Hi all,
I am trying to compare two strings/dates, but its throwing error::Syntax error at line 5:
Please help !!
Any alternate way to compare two dates is also fine....
logdate1=`date -u '+%Y.%m.%d %T'`
sleep 5
logdate2=`date -u '+%Y.%m.%d %T'`
if test... (5 Replies)
hi all,
i am new to unix. Actually i need to compare two string and print the result...
suppose type='sun'
if; then
echo good morning
else
echo good night
fi
whether the comparison is right r we need to use eq????
help me please.... :confused:
thanks in advance.... (1 Reply)