---
title: bash
---

bash strict mode
----------------

[unofficial bash strict mode](http://redsymbol.net/articles/unofficial-bash-strict-mode/)

(I generally don't set the IFS as recomended)

```
set -e #exit immediately if a simple command exits with a non-zero status
set -u #treat unset variables as an error when performing parameter expansion
set -o pipefail #exit status of last non-zero exit code is returned
```

create temp file
----------------

```
tempfile="$(/bin/mktemp)"
```

script name
-----------

strips of everything before the last "/"

```
scriptname="${0##*/}"
```

hostname
--------

```
#find our current host
fqdn="$(/bin/hostname)"
#strip off everything after the first "."
host="${fqdn%%.*}"
```

date time
---------

```
datetime="$(/bin/date "+%Y%m%dT%H%M%S")"
```

test its a number
-----------------

Useful for checking a number was passed from the cli

```
re='^[0-9]+$'
if ! [[ ${1} =~ $re ]] ; then
    echo "error: $0 NUMBER" >&2; exit 1
fi
```