need to keep the "0" in "01"

Thread Tools Search this Thread
Top Forums Shell Programming and Scripting need to keep the "0" in "01"
# 8  
Old 01-26-2008
01 and 1 are numerically equal, so should you be comparing numbers or strings? ''01" is not equal to "1", or does ksh not distinguish the difference?

On the same hand, this:


seems the same as:


I would think the leading 0 is silently dropped from the equation.
# 9  
Old 01-26-2008
The leading zero can be an issue. [ $MNTH = 01 ] will be true is MNTH is 01 but it will be false if MNTH is just 1. Instead of = you can use -eq like this: [ $MNTH -eq 1 ] and this is an integer compare rather than a string compare. But with many version of ksh a leading zero indicated an octal number so 09 is not a valid number with these versions. This is required by Posix so it may become more common.
# 10  
Old 01-26-2008
I did a little experimenting and these seem to evaluate to true:

((MNTH = 1))
MNTH=$(printf "%02d" $MNTH)
#echo $MNTH
if [ MNTH -eq "01" ]; then
   echo $MNTH
if [ MNTH -eq "1" ]; then
   echo $MNTH
if [ "$MNTH" == 01 ]; then
   echo $MNTH
if [ $MNTH == 01 ]; then
   echo $MNTH
if [ $MNTH = 01 ]; then
   echo $MNTH

Now I have never written a single line of ksh before this so I am not sure in what context those test conditions are being evaluated.
# 11  
Old 01-26-2008
Yeah but 1 in base 10 equals 1 in base 8. Try it with 09 to see if your ksh treats leading zeros as indicating octal. Also post your os version.
# 12  
Old 01-26-2008
These all seem to evaluate to true:

((MNTH = 9))
MNTH=$(printf "%02d" $MNTH)
echo $MNTH
if [ MNTH -eq "09" ]; then
   echo $MNTH
if [ MNTH -eq "9" ]; then
   echo $MNTH
if [ "$MNTH" == 09 ]; then
   echo $MNTH
if [ $MNTH == 09 ]; then
   echo $MNTH
if [ $MNTH = 09 ]; then
   echo $MNTH

I 'm testing on Linux but I don't know the version number.
# 13  
Old 01-28-2008
Thank you all for your help it is much appreciated!

Here is my summation of things, please feel free to correct me if I am wrong.
The format of $MNTH was `date +%m` which adds the "0"

The calculation with the "0" and without the "0" (01-01, 01-1, 1-1)
Mathmatical calculations will always drop the "0", which to me is a known, I just did not know if unix would hold the "0" in place once formated. (it does not Smilie )

With the help of Jim_M, I was able to reformat the date and put the "0" back in place.
Originally Posted by jim mcnamara
add a line
MNTH=$(printf "%02d" $MNTH)

However, this then provided with the problem - when $YEAR = "2009" and $MNTH = "01", my if statement outputed 00/2008 (which is obviously incorrect Smilie )
So.....with the help of Perderabo and his correction....below,
Originally Posted by Perderabo
Each item in the test must be separated by spaces.

wrong: [ $MNTH!=01 ]
right: [ $MNTH != 01 ]
Things seem to work know, I tested the following $MNTH and $YEAR values
01/2009 returned as 12/2008 Smilie
12/2008 returned as 11/2008 Smilie
10/2008 returned as 09/2008 Smilie
02/2008 returned as 01/2008 Smilie
03/2008 returned as 02/2008 Smilie

Thank you all for your help and support, I think I just felt another ripple on my brain form! Smilie

Here is what the if statement looks like now
if [ $MNTH != 01 ]
(( MNTH=$MNTH-01 ))
MNTH=$(printf "%02d" $MNTH)
if [ $MNTH = 01 ]
(( YEAR=$YEAR-1 ))


Last edited by cml2008; 01-28-2008 at 02:58 PM.. Reason: adding code
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. AIX

Apache 2.4 directory cannot display "Last modified" "Size" "Description"

Hi 2 all, i have had AIX 7.2 :/# /usr/IBMAHS/bin/apachectl -v Server version: Apache/2.4.12 (Unix) Server built: May 25 2015 04:58:27 :/#:/# /usr/IBMAHS/bin/apachectl -M Loaded Modules: core_module (static) so_module (static) http_module (static) mpm_worker_module (static) ... (3 Replies)
Discussion started by: penchev
3 Replies

2. Shell Programming and Scripting

Bash script - Print an ascii file using specific font "Latin Modern Mono 12" "regular" "9"

Hello. System : opensuse leap 42.3 I have a bash script that build a text file. I would like the last command doing : print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt where : print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
1 Replies

3. UNIX for Dummies Questions & Answers

Using "mailx" command to read "to" and "cc" email addreses from input file

How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address and column 3 contains “cc” e-mail address to include with same email. Sample input file, email.txt Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies

4. Solaris

The slices "usr", "opt", "tmp" disappeared!!! Help please.

The system don't boot. on the screen appears following: press enter to maintenance (or type CTRL-D to continue)...I checked with format command. ... the slices "0-root","1-swap","2-backup" exist. ...the slises "3-var","6-usr" -unassigned. :( (16 Replies)
Discussion started by: wolfgang
16 Replies

5. Shell Programming and Scripting

how to use "cut" or "awk" or "sed" to remove a string

logs: "/home/abc/public_html/index.php" "/home/abc/public_html/index.php" "/home/xyz/public_html/index.php" "/home/xyz/public_html/index.php" "/home/xyz/public_html/index.php" how to use "cut" or "awk" or "sed" to get the following result: abc abc xyz xyz xyz (8 Replies)
Discussion started by: timmywong
8 Replies

6. Shell Programming and Scripting

awk command to replace ";" with "|" and ""|" at diferent places in line of file

Hi, I have line in input file as below: 3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL My expected output for line in the file must be : "1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL" Can someone... (7 Replies)
Discussion started by: shis100
7 Replies

7. Shell Programming and Scripting

ps -ef | grep "string1" "string2" " "string3"

Hi all, can any one suggest me the script to grep multiple strings from ps -ef pls correct the below script . its not working/ i want to print OK if all the below process are running in my solaris system. else i want to print NOT OK. bash-3.00$ ps -ef | grep blu lscpusr 48 42 ... (11 Replies)
Discussion started by: steve2216
11 Replies

8. Shell Programming and Scripting

cat $como_file | awk /^~/'{print $1","$2","$3","$4}' | sed -e 's/~//g'

hi All, cat file_name | awk /^~/'{print $1","$2","$3","$4}' | sed -e 's/~//g' Can this be done by using sed or awk alone (4 Replies)
Discussion started by: harshakusam
4 Replies

9. UNIX for Dummies Questions & Answers

Explain the line "mn_code=`env|grep ""|awk -F"=" '{print $2}'`"

Hi Friends, Can any of you explain me about the below line of code? mn_code=`env|grep ""|awk -F"=" '{print $2}'` Im not able to understand, what exactly it is doing :confused: Any help would be useful for me. Lokesha (4 Replies)
Discussion started by: Lokesha
4 Replies
Login or Register to Ask a Question