Issue handling single quoted argument in shell script.


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# 1  
Issue handling single quoted argument in shell script.

Below is my script that works fine and prints the desired output:

Code:
#!/bin/ksh
echo "$1" |
  while IFS= read -r dirpath
do
  echo "DIRR_PATH:$dirpath"
  install_dir=$install_dir" "$dirpath
done
echo "Desired Output:$install_dir"

Output:
Code:
./loopissue.sh "/tmp/scripts\\n/tmp/mrt\\n/tmp/exe"
DIRR_PATH:/tmp/scripts
DIRR_PATH:/tmp/mrt
DIRR_PATH:/tmp/exe
Desired Output:/tmp/scripts /tmp/mrt /tmp/exe

The problem is i'm not getting a clean way to seperate the arguments with a single white space as seen in the "desired output:" above when the parameters are passed in single qoutes like below:

Code:
./loopissue.sh '/tmp/scripts\\n/tmp/mrt\\n/tmp/exe'

I'm on Aix6.1 and ksh shell.

Can you please suggest how can I get similar output when the argument is passed in single quotes ?

I tried removing the single quotes using the below two approaches but that did not help.
Code:
sed "s/'//g"
tr -d"'"

In Summary: All \\n should be replaced by single white space and single quotes should be removed from the argument and stored in a variable.

Last edited by mohtashims; 10-01-2019 at 09:51 AM..
# 2  
In single quotes you must not \escape the \escape:
Code:
./loopissue.sh '/tmp/scripts\n/tmp/mrt\n/tmp/exe'

The shell removes the 'single quotes' and the "double quotes" before it invokes the loopissue.sh. The quotes are only the hint to pass it as one string - to $1 in the loopissue.sh.
Also the following works (and is even better portable, because the \n must be interpreted by the echo command):
Code:
./loopissue.sh '/tmp/scripts
/tmp/mrt
/tmp/exe'

Is there a reason to squeeze all arguments into one $1?
Maybe you can simply use
Code:
./loopissue.sh /tmp/scripts /tmp/mrt /tmp/exe

This maps to $1 $2 $3 in the loopissue.sh
And it's simple to print them in different formats:
Code:
#!/bin/ksh
for dirpath
do
  echo "DIRR_PATH:$dirpath"
done
echo "Desired Output:$@"

Note that for dirpath is short for for dirpath in "$@". In other words, a for loop defaults to loop thru all arguments.
# 3  
Quote:
Originally Posted by MadeInGermany
In single quotes you must not \escape the \escape:
Code:
./loopissue.sh '/tmp/scripts\n/tmp/mrt\n/tmp/exe'

The shell removes the 'single quotes' and the "double quotes" before it invokes the loopissue.sh. The quotes are only the hint to pass it as one string - to $1 in the loopissue.sh.
Also the following works (and is even better portable, because the \n must be interpreted by the echo command):
Code:
./loopissue.sh '/tmp/scripts
/tmp/mrt
/tmp/exe'

Is there a reason to squeeze all arguments into one $1?
Maybe you can simply use
Code:
./loopissue.sh /tmp/scripts /tmp/mrt /tmp/exe

This maps to $1 $2 $3 in the loopissue.sh
And it's simple to print them in different formats:
Code:
#!/bin/ksh
for dirpath
do
  echo "DIRR_PATH:$dirpath"
done
echo "Desired Output:$@"

Note that for dirpath is short for for dirpath in "$@". In other words, a for loop defaults to loop thru all arguments.
The arguments passed to the script come from the database in the format I shared and cannot be changed hence the proposed solution would not work.

Is there a way to replace all \\n to single whitespace as requested in the original post?
# 4  
Hi,

Is this what you are expecting;

Code:
#!/bin/ksh
VAR1=`echo -e "${1}" | sed -e "s/'//g"`
echo -e "${VAR1}" |
  while IFS=' '
read -r dirpath
do
  echo "DIRR_PATH:$dirpath"
  install_dir=$install_dir" "$dirpath
done
echo "Desired Output:$install_dir"

Where it is run as;

Code:
./tester.sh '/tmp/scripts\\n/tmp/mrt\\n/tmp/exe'

With this as the Output;

Code:
DIRR_PATH:/tmp/scripts
DIRR_PATH:/tmp/mrt
DIRR_PATH:/tmp/exe
Desired Output: /tmp/scripts /tmp/mrt /tmp/exe

Regards

Gull04

Last edited by gull04; 10-01-2019 at 01:21 PM.. Reason: Posted Wrong Code
# 5  
Why not simply
Code:
installdir=${1//\\\\n/ }

?
These 2 Users Gave Thanks to RudiC For This Post:
# 6  
Nice RudiC, if OP needs support for both double and single quotes on call:

Code:
#!/bin/ksh
install_dir=${1//\\\\n/ }
install_dir=${install_dir//\\n/ }
printf "DIRR_PATH:%s\n" $install_dir
echo "Desired Output:$install_dir"

Code:
$ ./loopissue.sh '/tmp/scripts\\n/tmp/mrt\\n/tmp/exe'
DIRR_PATH:/tmp/scripts
DIRR_PATH:/tmp/mrt
DIRR_PATH:/tmp/exe
Desired Output:/tmp/scripts /tmp/mrt /tmp/exe

$ ./loopissue.sh "/tmp/scripts\\n/tmp/mrt\\n/tmp/exe"
DIRR_PATH:/tmp/scripts
DIRR_PATH:/tmp/mrt
DIRR_PATH:/tmp/exe
Desired Output:/tmp/scripts /tmp/mrt /tmp/exe

# 7  
Quote:
Originally Posted by RudiC
Why not simply
Code:
installdir=${1//\\\\n/ }

?
Getting error:
Quote:
loopissue.sh[55]: install_dir=${1//\\\\n/ }: bad substitution
--- Post updated at 02:53 AM ---

Quote:
Originally Posted by gull04
Hi,

Is this what you are expecting;

Code:
#!/bin/ksh
VAR1=`echo -e "${1}" | sed -e "s/'//g"`
echo -e "${VAR1}" |
  while IFS=' '
read -r dirpath
do
  echo "DIRR_PATH:$dirpath"
  install_dir=$install_dir" "$dirpath
done
echo "Desired Output:$install_dir"

Where it is run as;

Code:
./tester.sh '/tmp/scripts\\n/tmp/mrt\\n/tmp/exe'

With this as the Output;

Code:
DIRR_PATH:/tmp/scripts
DIRR_PATH:/tmp/mrt
DIRR_PATH:/tmp/exe
Desired Output: /tmp/scripts /tmp/mrt /tmp/exe

Regards

Gull04
@Gull04: I tried your option but i get -e -e before the first element. Please see output below:

Quote:
DIRR_PATH:-e -e /tmp/scripts
DIRR_PATH:/tmp/mrt
DIRR_PATH:/tmp/exe
Desired Output: -e -e /tmp/scripts /tmp/mrt /tmp/exe
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