Execute and log a command in bash

Question

I'm doing some data analysis in bash with various tools and every now and then I enter something like

>some_command -with -complicated -arguments

Often I immediately follow this up with

>echo "some_command -with -complicated -arguments" >> mylog.txt

Is there any way to do this all at once? It's a pain to hit the up arrow, add echo and quotes so forth.

I don't want to log my entire session, I should add, because there would be a lot of stuff not worth recording.

check out the `history` command as well as the .bash_history file — CoconutBandit, Jan 27 '17 at 19:50
Cross-site duplicate: http://unix.stackexchange.com/questions/38072/how-can-i-save-the-last-command-to-a-file — Charles Duffy, Jan 27 '17 at 20:00
Local very-near-duplicate (answering the other makes the answer to this one obvious): http://stackoverflow.com/questions/40715729/linux-store-last-command-into-variable — Charles Duffy, Jan 27 '17 at 20:01
likewise, http://stackoverflow.com/questions/6756360/how-do-i-get-previous-executed-command-in-a-bash-script — Charles Duffy, Jan 27 '17 at 20:03

score 0 · Answer 1 · answered Jan 27 '17 at 19:53

0

verbose () {
  echo "$@" >> mylogfile
  "$@"
}

verbose sleep 1 # "sleep 1" is the example command

answered Jan 27 '17 at 19:53

DigitalRoss

1

This will log `-foo "bar baz"` identically to `-foo bar baz`. – Charles Duffy Jan 27 '17 at 19:55
1

If you just need semantic equivalence to the command the user ran, consider: `verbose() { local cmd_q; printf -v cmd_q '%q ' "$@"; printf '%s\n' "${cmd_q% }" >>mylogfile; "$@"; }` -- but that's just semantic equivalence, it's not the precise text (and, say, `verbose cat - "$(something)" >elsewhere` won't log either the redirection *or* the knowledge that it was the output of `something` used to form the last argument before said redirection). – Charles Duffy Jan 27 '17 at 19:58
Yeah this is a problem. For example `sed -i "s/Alice/Bob/g" test.txt` is logged as `sed -i s/Alice/Bob/g test.txt`. I'd like the exact original command stored. – Ben S. Jan 27 '17 at 20:13

score 0 · Accepted Answer · answered Jan 29 '17 at 20:58

Following the references pointed out by Charles Duffy, I ended up adding this to my .bashrc:

logit() {
    fc -ln -1 | sed '1s/^[[:space:]]*//' >> ${1:-commands.txt}
}

So logit by itself will add the last command to commands.txt, and logit myfile will add the last command to myfile.

2 Answers2