nested 'if' statements in a shell script?

[doubleudee1]

I want to move some files from one directory to another, I have the names of the diectories in variables, but initally I am testing it with the code below but am getting the errors show.
How is nesting achived so i can run a statement such as below (the loop to change files & directories is not shown but that does work to chnge them as required)

This is my test code:

Code: Select all

aa="201901"
bb="201902"
cc="201903"


if [ ${j} == ${aa} ]
 then echo "aa moved"  ##mv  "${m}" "${n}"        #########commected out for testing
  elif [ ${j} == ${bb} ]
 then echo "bb moved"  ##mv  "${m}" "$[n}"        #########commected out for testing
  elif [ ${j} == ${cc} ]
 then echo "cc moved"  ##mv  "${m}" "${n}"         #########commected out for testing
##  elif j == "201904" mv -1 "{l}" "n"
##  elif j == "201905" mv -1 "{l}" "n"
##  elif j == "201906" mv -1 "{l}" "n"
##  elif j == "201907" mv -1 "{l}" "n"
##  elif j == "201908" mv -1 "{l}" "n"
##  elif j == "201909" mv -1 "{l}" "n"
##  elif j == "201910" mv -1 "{l}" "n"
##  elif j == "201911" mv -1 "{l}" "n"
##  elif j == "201912" mv -1 "{l}" "n"
else: echo "No Files Left To Move"
fi
############# OUTPUTTED errors in above #############
cc moved
./CreatejpgDirs: line 44: else:: command not found

[RaTTuS]

http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO-6.html
else:
is not else

[B.Goode]

This is a shell script?

See the documentation in man bash

This is the description for if..then..else

if list; then list; [ elif list; then list; ] ... [
else list; ] fi
The if list is executed. If its exit status
is zero, the then list is executed. Other‐
wise, each elif list is executed in turn, and
if its exit status is zero, the corresponding
then list is executed and the command com‐
pletes. Otherwise, the else list is exe‐
cuted, if present. The exit status is the
exit status of the last command executed, or
zero if no condition tested true.

Maybe it is the extraneous ':' that is the stumbling block?

(Turns out someone else has pointed this out more pithily while I was researching... )

[doubleudee1]

http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO-6.html
else:
is not else

So I have to have one 'if' ....... 'fi' statement for every change I want to make?
I only used the elif as I thought I could nest all changes in one 'if' ...... 'fi' statement, or is there an alternataive statement I should be using to make all the changes within it?

Sorry, just saw second reply

so I can do

Code: Select all

aa="201901"
bb="201902"
cc="201903"


if [ ${j} == ${aa} ]
 then echo "aa moved"  ##mv  "${m}" "${n}"        #########commected out for testing
  [ ${j} == ${bb} ]
 then echo "bb moved"  ##mv  "${m}" "$[n}"        #########commected out for testing
  [ ${j} == ${cc} ]
 then echo "cc moved"  ##mv  "${m}" "${n}"         #########commected out for testing
 else echo "No Files Left To Move"
fi

[RaTTuS]

no you can have elif , you just need to get else correct
bash is very particular about spaces

[Roken]

case may be a better solution for this: https://www.tldp.org/LDP/Bash-Beginners ... 07_03.html

[epoch1970]

Agreed, case is more portable, more readable and executes faster.

Code: Select all

case "${j}" in
	201901)
		echo "aa moved"
		;;
	201902)
		echo "bb moved"
		;;
	201903)
		echo "cc moved"
		;;
	*)
		echo "${j}: No Files Left To Move"
		;;
esac

Its only weakness is limited pattern-matching capability, e.g. patterns like "20190?)" or "2019*)" are ok but much more.
Nested case statements are possible and still sort-of-readable.