I am trying to save all output of a collection to separate files. For example one function will be like:
function kernel_info(){
echo "Kernel version: $(uname -v)"
}
I want to write this output to file which will have kernel_info as it name. Similarly I will create other functions to gather other information like hostname, etc. How can I write a function which I can call every time I want to save the information to a file on disk? Thanks
Use tee.
kernel_info () {
{ printf 'Kernel version: '
uname -v
} | tee -a /path/to/kernel_info
}
This function will write the combined output of printf and uname to the given file, and continue to write the same to standard output.
The -a option makes tee append to the file.
If you want to parameterize the function, you can.
kernel_info () {
local fname
fname=${1:-/default/path/to/kernel_info}
{ printf 'Kernel version: '
uname -v
} | tee -a "$fname"
}
kernel_info # Writes to /default/path/to/kernel_info
kernel_info /var/log/kernel_info # Write to an alternate file
fname, shouldn't that be local?
local.local also as the "distinction" of being the only non-POSIX part of the answer.)You can automate the naming via perusing How to determine function name from inside a function - and simply
... | tee "${FUNCNAME}.log"
within the function where you'd like to log to a specifically-named output file.
Define a list of functions to loop over then call them and then redirect the result into a file,
> replace, >> append
#!/bin/bash
function local_hostname() {
echo "Hostname: $(hostname)"
}
function kernel_info() {
echo "Kernel version: $(uname -v)"
}
function write_to_file() {
> file.txt
funcs=(
local_hostname
kernel_info
)
for func in ${funcs[*]}
do
$func >> file.txt
done
}
write_to_file
You can keep it simple...
$: tst() { date ; } >>log
$: ls -l log
ls: cannot access 'log': No such file or directory
$: tst
$: cat log
Wed, Jun 17, 2020 8:12:10 AM
$: tst
$: cat log
Wed, Jun 17, 2020 8:12:10 AM
Wed, Jun 17, 2020 8:12:17 AM
