I recommend using “mkdir -p” instead – in your example, if /var or /var/cache were missing it would create these parts of the path too, otherwise your command might fail…

[ -d "/var/cache/git" ] || mkdir /var/cache/git

ls | grep -e .5.

.5. gets expanded inline, -unless- it fails to match

When using test(1) without then, as a course of proper style, I prefer to use test rather than [. This leads to better lines IMO:

test -e $DIR && echo 'true' || echo 'false'

which is simply the same semantic as:

if [ -e $DIR ]; then echo ‘true’; else echo ‘false’; fi

which interestingly, could be written:

if test -e $DIR; then echo 'true'; else echo 'false'; fi

[ is not known as a test, [ is test(1). less(1) is more(1), and so on.

if, then, else, and fi are bash(1) special, and in most sh(1) implementations, actually sh(1) special too.

Instead of always writing echo 'yes' and so on, you could make an alias or a command, called 'h' (for 'human') or some such) which takes an exit status, and outputs a human oriented value, e.g.

test -e $DIR; h # => 'YES'

alias h='v=$?; if [ $v -eq 0 ]; then echo YES; else if [ $v -eq 1 ]; then echo NO; else echo ERR; fi; fi'

"(xargs passes each line as an argument into EACH touch)"

on the contrary, xargs by default appends all line separated arguments to a single call to it's given command line.

The xargs from a text file example could simply be re-written:

touch cat my_file_list.txt

People often start using xargs where they don't need to...

replacing spaces in file names:

for i in *\ *; do mv $i ${i// /_}; done

As far as echo's -e argument being undocumented goes, well, that's not true, if you read the manpage for echo(1) on most systems, it'll say:

"Some shells may provide a builtin echo command which is similar or identical to this util-ity."

And find(1) has an -exec argument.

Visit Emson.co.uk for having useful tips on bash scripts for web developers. …