If you are die hard Bourne Shell (/bin/sh) scripter, it can be a challenge not to be enticed by the syntax niceties of the Born Again Borne Shell (/bin/bash).
One example is the `{..} syntax</code for simple for loops.
#!/bin/bash
for I in {0..5}
do
echo $I
done
0 1 2 3 4 5
This syntax is not valid in /bin/sh` on Linux.
#!/bin/sh
for I in {0..5}
do
echo $I
done
{0..5}
NOTE: However apparently it does work in Mac OS X, which is derived from BSD, not Linux.
/bin/sh gives you a for loop but it requires the full list of iterated values instead of a range.
#!/bin/sh
for I in 0 1 2 3 4 5
do
echo $I
done
Note: Passing a string does not work by default.
#!/bin/sh
for I in "0 1 2 3 4 5"
do
echo $I
done
The approach to product the same result requires some format management.
#!/bin/sh
OIFS=$IFS
IFS=" "
for I in `echo "0 1 2 3 4 5"`
do
echo $I
done
IFS=$OIFS
You can use while
#!/bin/sh
I=0
while [ $I -le 5 ]
do
echo $I
I=`expr $I + 1`
done
You can use one of several other shell commands, in this example awk
#!/bin/sh
for I in `awk 'BEGIN{for (i=0;i<=5;i++) print i}'`
do
echo $I
done
Or, the function specifically design for sequences of numbers seq
#!/bin/sh
for I in `seq 0 5`
do
echo $I
done
And for these few examples, there will be more possibilities to achieve close to feature parity of the /bin/bash syntax.
An example found on BSD is jot - 0 5. This is not available Ubuntu by default but installed with the athena-jot package. However the syntax is then different for correct usage.
