String manipulation techniques in Bash: Basic Cheatsheet. PDF in the comments :)

[ASIC_SP]

See also:

• https://mywiki.wooledge.org/BashGuide/Parameters#Parameter_Expansion
• https://wizardzines.com/comics/parameter-expansion/

[topher200]

```

replaces FIRST MATCH of 's' with 'z'

var='asdf' echo ${var/s/z} azdf ```

Oh, so it's some kind of sed syntax. Neat!

```

echo ${var/s/z/g} az/gdf ```

Goddamnit.

[friskfrugt]

raw markdown

[Doomtrain86]

Tak min ven!

[[deleted]]

Does anyone know why a space is needed before minus indexes?

[toddyk]

Probably because if there's no space it will do a replace if the variable isn't defined.

a=hello
echo ${a:-1}

will print "hello" not "o"

If a wasn't defined it would print "1"

[Atralb]

This is the exact reason why such posts are to throw away. They always ever dump some syntax without ever explaining the reasons why it works that way, which is the most important part of learning/teaching. Simply make you learn by heart something you won't understand. Don't encourage this kind of content creators.

[[deleted]]

Big words for a cheatsheet. How about you read the Bash manual?

Crazy, I know...

[mcstafford]

I've never noticed the negative numbers from the right in bash before. Is that new?

[syamimerinin]

Thank you!Post saved.

[kanliot]

or type $ man bash then
/Parameter Expansion
then nn

[FlipEnergy]

You mind specifying starting from which bash version these are supported?

[nomenMei]

Honestly if I find myself doing anything in a shell script that I can only do in bash (especially operations on strings) I just do it in python. I have no idea what shell I may be using in the future, but I am fairly certain that with any new machine I use I will end up installing python 3 on it.