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2024-07-23
Bash - cheat sheet
Contents
Arguments
| variable |
description |
$0 |
name of the script |
$1 |
first argument |
$2 |
second argument |
$<n> |
<nth> argument, where n > 0 |
$@ |
all arguments as one string |
$# |
count of arguments |
Example
#!/bin/bash
echo script started with $# args: $@
for arg in "$@"; do
echo "$arg"
done
# $ ./script.sh --config=test --verbose 1 2
# script started with 4 args: --config=test --verbose 1 2
# --config=test
# --verbose
# 1
# 2
Conditionals
if [[ <CONDITION> ]]; then
...
elif [[ <CONDITION> ]]; then
...
else
...
fi
| condition |
description |
"$VAR" == "STRING" |
compare content of env var with string |
-z "$VAR" |
test if string length is zero |
-n "$VAR" |
test if string length is not zero |
-f "$VAR" |
test if regular file exist |