wlan-141056:part_u_2 prova$ ls -2e-5_cas 0_cas 10e-5_cas 20e-5_cas 40e-5_cas 5e-5_cas wlan-141056:part_u_2 prova$ cat -2e-5_cas 0_cas > prova cat: illegal option -- 2 usage: cat [-benstuv] [file ...]
What's wrong with merging two files using cat ?
The first file you want to
cat starts with a
cat considers it to be an option. But as there is no option
2 (see the usage string) it throws an error.
Use one of
cat ./-2e-5_cas 0_cas > prova cat -- -2e-5_cas 0_cas > prova
instead (the second is better for scripts etc).
PS: In general it is recommend to not use
- as the first character of a filename to prevent exactly these issues.