About
My everyday development environment consists of a lot of different machines -- OS X Leopard, OS X Snow Leopard, Arch Linux, Gentoo Linux, Debian Linux, Ubuntu Linux, mingw on win32, (cygwin on win32, shudder), and embedded systems with busybox (or toolbox, on my G1).
These all can use slightly different versions of shells, and I like to keep my scripts portable so if I had to run a different one, it wouldn't be painful. It also helps with CI software to be able to add new buildslaves at any time.
Command Bash 3.x Zsh Dash Busybox
------- -------- --- ---- -------
echo {1..3} YES YES no no
seq 1 3 -- coreutils?
jot 3 -- bsd
perl -e "print join ' ', 1..3" -- anywhere with perl
Command Output Bash 3.x Zsh Dash Busybox Sh
------- -------- --- ---- ------- --
`echo 1` YES YES YES YES YES
$(echo 1) YES YES YES YES no
Math operation Bash 3.x Zsh Dash Busybox
------- -------- --- ---- -------
$(( $x + 1 )) YES YES YES YES
let t="$x+1" YES no no YES
echo "1 + 2" | bc
echo "$x 1 + p" | dc
Spaces in filesBash 3.x Zsh Dash Busybox
------- -------- --- ---- -------
ls | while read r; do echo "$r"; done
YES no YES YES
IFS="\n"; for f in `ls`; do echo "$f"; done
YES YES YES YES
Dir of a scriptBash 3.x Zsh Dash Busybox
------- -------- --- ---- -------
x=$(cd `dirname $0`; pwd)
YES ?? ?? ??
Predicated removal
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find . -name '*.pyc' | while read r; do if [ ! -f `echo $$r | sed -e 's/pyc$/py/'` ]; then rm "$r"; done
find . -name '*.pyc' | while read r; do if [ ! -f "${r/%pyc/py}" ]; then rm "$r"; done
Catting a file
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cat filename -- everywhere except an openwrt micro build
grep -v IMPOSSIBLE filename
Copying a file
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cp file newfile -- anywhere except stock G1
cat file > newfile
install ...