In a shell script: echo shell commands as they are executed
In a shell script how do I echo all shell commands called and expand any variable names? For example, given the following line:
ls $DIRNAME
I would like the script to run the command and display the following
ls /full/path/to/some/dir
The purpose is to save a log of all shell commands called and their arguments. Perhaps there is a better way of generating such aa log?
set -x or set -o xtrace expands variables and prints a little + sign before the line.
set -v or set -o verbose does not expand the variables before printing.
Use set +x and set +v to turn off the above settings.
On the first line of the script, one can put #!/bin/sh -x (or -v ) to have the same effect as set -x (or -v ) later in the script.
The above also works with /bin/sh .
http://www.faqs.org/docs/abs/HTML/options.html
$ cat shl
#!/bin/bash
DIR=/tmp/so
ls $DIR
$ bash -x shl
+ DIR=/tmp/so
+ ls /tmp/so
$
set -x will give you what you want.
Here is an example shell script to demonstrate:
#!/bin/bash
set -x #echo on
ls $PWD
This expands all variables and prints the full commands before output of the command.
output:
+ ls /home/user/
file1.txt file2.txt
你也可以在你的脚本中通过将它们包装在set -x和set +x来切换这些行
#!/bin/bash
...
if [[ ! -e $OUT_FILE ]];
then
echo "grabbing $URL"
set -x
curl --fail --noproxy $SERV -s -S $URL -o $OUT_FILE
set +x
fi