Notes

Everyday commands I use at work, up to seven per topic. Replace anything in angle brackets.

Read a file
cat for short files, less to scroll long ones (q to quit).
```
cat config.yaml
less app.log
```
Start, end and live tail
Check the latest lines of a log as they arrive.
```
head -n 20 app.log
tail -n 50 app.log
tail -f app.log
```
Search inside files
Recursive, with line numbers, case-insensitive.
```
grep -rni "error" ./logs
```
Edit a file
nano is simplest; in vim press i to edit, Esc then :wq to save.
```
nano config.yaml
vim config.yaml
```
Replace text in a file
Every match, in place.
```
sed -i 's/old/new/g' config.yaml
```
File, folder and disk sizes
Human-readable sizes.
```
ls -lh
du -sh *
df -h
```
Find files
By name or by size.
```
find . -name "*.log"
find . -size +100M
```