84 lines
1.1 KiB
Markdown
84 lines
1.1 KiB
Markdown
---
|
|
title: "conditionals"
|
|
tags: [ "Documentation", "Basics" ]
|
|
---
|
|
# If statements
|
|
|
|
Test statement equality as so:
|
|
|
|
```
|
|
|
|
read t1
|
|
read t2
|
|
if test $t1 != $t2; then
|
|
echo 'variables do not match'
|
|
else
|
|
echo 'variables match'
|
|
fi
|
|
exit 0
|
|
|
|
```
|
|
|
|
# Case Structure
|
|
|
|
These deal with multiple states rather than forking conditions.
|
|
|
|
Example:
|
|
|
|
```
|
|
|
|
#!/bin/bash
|
|
|
|
# Simple case demonstration
|
|
|
|
echo "What's your favourite creature?"
|
|
read CRE
|
|
case $CRE in
|
|
human | humanoids ) echo "Why is $CRE always standard?"
|
|
;;
|
|
troll | monsters ) echo "Not exactly known for their character ..."
|
|
;;
|
|
owlbears | monsters ) echo "Really you're a wizard fan"
|
|
;;
|
|
esac
|
|
|
|
# While and Until
|
|
This prints from 1 until 9.
|
|
|
|
> COUNTER=1
|
|
|
|
> while [ $COUNTER -lt 2 ]; do
|
|
|
|
> ((COUNTER++))
|
|
|
|
> echo $COUNTER
|
|
|
|
> done
|
|
|
|
```
|
|
|
|
There's also 'until', which stops when something is true, rather than keeping going when something is true.
|
|
|
|
# For
|
|
|
|
> for i in $( ls ); do
|
|
> du -sh $i
|
|
> done
|
|
|
|
# Sequences
|
|
|
|
The sequences tool counts up from X in jumps of Y to number Z.
|
|
|
|
Count from 1 to 10.
|
|
|
|
> seq 10
|
|
|
|
Count from 4 to 11.
|
|
|
|
> seq 4 11
|
|
|
|
Count from 1 to 100 in steps of 5.
|
|
|
|
> seq 1 5 100
|
|
|